Atom or group transfer radical polymerization

ABSTRACT

Improved processes have been developed for atom (or group) transfer radical polymerization (ATRP). In one improvement, the ATRP process involves polymerizing in the presence of a (partially) free radical-deactivating amount of the corresponding reduced or oxidized transition metal compound. In a further improvement, the ATRP process involves polymerizing in a homogeneous system or in the presence of a solubilized initiating/catalytic system. The present invention also concerns end-functional, site-specific functional and telechelic homopolymers and copolymers; block, random, graft, alternating and tapered (or “gradient”) copolymers which may have certain properties or a certain novel structure; star, comb and “hyperbranched” polymers and copolymers; multi-functional hyperbranched, end-functional polymers; cross-linked polymers and gels; water-soluble polymers and hydrogels (e.g., a copolymer prepared by radical copolymerization of a water-soluble monomer and a divinyl monomer); and an ATRP process using water as a medium.

This application is a Divisional application of U.S. application Ser.No. 08/559,309, filed Nov. 15, 1995, now U.S. Pat. No. 5,807,937, theentire contents of which are incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention concerns novel (co)polymers and a novel radicalpolymerization process based on transition metal-mediated atom or grouptransfer polymerization (“atom transfer radical polymerization”).

2. Discussion of the Background

Living polymerization renders unique possibilities of preparing amultitude- of polymers which are well-defined in terms of moleculardimension, polydispersity, topology, composition, functionalization andmicrostructure. Many living systems based on anionic, cationic andseveral other types of initiators have been developed over the past 40years (see O. W. Webster, Science, 251, 887 (1991)).

However, in comparison to other living systems, living radicalpolymerization represented a poorly answered challenge prior to thepresent invention. It was difficult to control the molecular weight andthe polydispersity to achieve a highly uniform product of desiredstructure by prior radical polymerization processes.

On the other hand, radical polymerization offers the advantages of beingapplicable to polymerization of a wide variety of commercially importantmonomers, many of which cannot be polymerizediby other polymerizationprocesses. Moreover, it is easier to make random copolymers by radicalpolymerization than by other (e.g., ionic) polymerization processes.Certain block copolymers cannot be made by other polymerizationprocesses. Further, radical polymerization processes can be conducted inbulk, in solution, in suspension or in an emulsion, in contrast to otherpolymerization processes.

Thus, a need is strongly felt for a radical polymerization process whichprovides (co)polymers having a predetermined molecular weight, a narrowmolecular weight distribution (low “polydispersity”), various topologiesand controlled, uniform structures.

Three approaches to preparation of controlled polymers in a “living”radical process have been described (Greszta et al, Macromolecules, 27,638 (1994)). The first approach involves the situation where growingradicals react reversibly with scavenging radicals to form covalentspecies. The second approach involves the situation where growingradicals react reversibly with covalent species to produce persistentradicals. The third approach involves the situation where growingradicals participate in a degenerative transfer reaction whichregenerates the same type of radicals.

There are some patents and articles on living/controlled radicalpolymerization. Some of the best-controlled polymers obtained by“living” radical polymerization are prepared with preformed alkoxyaminesor are those prepared in situ (U.S. Pat. No. 4,581,429; Hawker, J. Am.Chem. Soc., 116, 11185 (1994); Georges et al, WO 94/11412; Georges etal, Macromolecules, 26, 2987 (1993)). A Co-containing complex has beenused to prepare “living” polyacrylates (Wayland, B. B., Pszmik, G.,Mukerjee, S. L., Fryd, M. J. Am. Chem. Soc., 116, 7943 (1994)). A“living” poly(vinyl acetate) can be prepared using an Al(i-Bu)₃:Bpy,:TEMPO initiating system (Mardare et al, Macromolecules, 27, 645(1994)). An initiating system based on benzoyl peroxide and chromiumacetate has been used to conduct the controlled radical polymerizationof methyl methacrylate and vinyl acetate (Lee et al, J. Chem. Soc.Trans. Faraday Soc. I, 74, 1726 (1978); Mardare et al, Polym. Prep.(ACS), 36(1) (1995)).

However, none of these “living” polymerization systems include an atomtransfer process based on a redox reaction with a transition metalcompound.

One paper describes a redox iniferter system based on Ni(0) and benzylhalides. However, a very broad and bimodal molecular weight distributionwas obtained, and the initiator efficiency based on benzyl halides usedwas about 1-2% or less (T. Otsu, T. Tashinori, M. Yoshioka, Chem.Express 1990, 5(10), 801). Tazaki et al (Mem. Fac. Eng., Osaka CityUniv., vol. 30 (1989), pages 103-113) disclose a redox iniferter systembased on reduced nickel and benzyl halides or xylylene dihalides. Theexamples earlier disclosed by Tazaki et al do not include a coordinatingligand. Tazaki et al also disclose the polymerization of styrene andmethyl methacrylate using their iniferter system.

These systems are similar to the redox initiators developed early(Bamford, in Comprehensive Polymer Science, Allen, G., Aggarwal, S. L.,Russo, S., eds., Pergamon: Oxford, 1991, vol. 3, p. 123), in which thesmall amount of initiating radicals were generated by redox reactionbetween (1) RCHX₂ or RCX₃ (where X=Br, Cl) and (2) Ni(0) and othertransition metals. The reversible deactivation of initiating radicals byoxidized Ni is very slow in comparison with propagation, resulting invery low initiator efficiency and a very broad and bimodal molecularweight distribution.

Bamford (supra) also discloses a Ni[P(OPh)₃]₄/CCl₄ or CBr₄ system forpolymerizing methyl methacrylate or styrene, and use of Mo(CO)_(n) toprepare a graft copolymer from a polymer having a brominated backboneand as a suitable transition metal catalyst for CCl₄, CBr₄ or CCl₃CO₂Etinitiators for polymerizing methyl methacrylate. Organic halides otherthan CCl₄ and CBr₄ are also disclosed. Mn₂(CO)₁₀/CCl₄ is taught as asource of CCl₃ radicals. Bamford also teaches that systems such asMn(acac)₃ and some vanadium (V) systems have been used as a source ofradicals, rather than as a catalyst for transferring radicals.

A number of the systems described by Bamford are “self-inhibiting”(i.e., an intermediate in initiation interferes with radicalgeneration). Other systems require coordination of monomer and/orphotoinitiation to proceed. It is further suggested that photoinitiatingsystems result in formation of metal-carbon bonds. In fact, Mn(CO)₅Cl, athermal initiator, is also believed to form Mn—C bonds under certainconditions.

In each of the reactions described by Bamford, the rate of radicalformation appears to be the rate-limiting step. Thus, once a growingradical chain is formed, chain growth (propagation) apparently proceedsuntil transfer or termination occurs.

Another paper describes the polymerization of methyl methacrylate,initiated by CCl₄ in the presence of RuCl₂(PPh₃)₃. However, the reactiondoes not occur without methylaluminum bis(2,6-di-tert-butylphenoxide),added as an activator (see M. Kato, M. Kamigaito, M. Sawamoto, T.Higashimura, Macromolecules, 28, 1721 (1995)).

U.S. Pat. No. 5,405,913 (to Harwood et al) discloses a redox initiatingsystem consisting of Cu^(II) salts, enolizable aldehydes and ketones(which do not contain any halogen atoms), various combinations ofcoordinating agents for Cu^(II) and Cu^(I), and a strong amine base thatis not oxidized by Cu^(II). The process of Harwood et al requires use ofa strong amine base to deprotonate the enolizable initiator (thusforming an enolate ion), which then transfers a single electron toCu^(II), consequently forming an enolyl radical and Cu^(I). The redoxinitiation process of Harwood et al is not reversible.

In each of the systems described by Tazaki et al, Otsu et al, Harwood etal and Bamford, polymers having uncontrolled molecular weights andpolydispersities typical for those produced by conventional radicalprocesses were obtained (i.e., >1.5). Only the system described by Katoet al (Macromolecules, 28, 1721 (1995)) achieves lower polydispersities.However, the polymerization system of Kato et al requires an additionalactivator, reportedly being inactive when using CCl₄, transition metaland ligand alone.

Atom transfer radical addition, ATRA, is a known method forcarbon-carbon bond formation in organic synthesis. (For reviews of atomtransfer methods in organic synthesis, see Curran, D. P. Synthesis,1988, 489; Curran, D. P. in Free Radicals in Synthesis and Biology,Minisci, F., ed., Kluwer: Dordrecht, 1989, p. 37; and Curran, D. P. inComprehensive Organic Synthesis, Trost, B. M., Fleming, I., eds.,Pergamon: Oxford, 1991, Vol. 4, p. 715.) In a very broad class of ATRA,two types of atom transfer methods have been largely developed. One ofthem is known as atom abstraction or homolytic substitution (see Curranet al, J. Org. Chem., 1989, 54, 3140; and Curran et al, J. Am. Chem.Soc., 1994, 116, 4279), in which a univalent atom (typically a halogen)or a group (such as SPh or SePh) is transferred from a neutral moleculeto a radical to form a new σ-bond and a new radical in accordance withScheme 1 below:

In this respect, iodine atom and the SePh group were found to work verywell, due to the presence of very weak C—I and C—SePh bonds towards thereactive radicals (Curran et al, J. Org. Chem. and J. Am. Chem. Soc.,supra). In earlier work, the present inventors have discovered thatalkyl iodides may induce the degenerative transfer process in radicalpolymerization, leading to a controlled radical polymerization ofseveral alkenes. This is consistent with the fact that alkyl iodides areoutstanding iodine atom donors that can undergo a fast and reversibletransfer in an initiation step and degenerative transfer in apropagation step (see Gaynor et al, Polym. Prep. (Am. Chem. Soc., Polym.Chem. Div.), 1995, 36(1), 467; Wana et al, Polym. Prep. (Am. Chem. Soc.,Polym. Chem. Div.), 1995, 36(1), 465; Matyjaszewski et al,Macromolecules, 1995, 28, 2093). By contrast, alkyl bromides andchlorides are relatively inefficient degenerative transfer reagents.

Another atom transfer method is promoted by a transition metal species(see Bellus, D. Pure & Appl. Chem. 1985, 57, 1827; Nagashima, H.; Ozaki,N.; Ishii, M.; Seki, K.; Washiyama, M.; Itoh, K. J. Org. Chem. 1993,58,.464; Udding, J. H.; Tuijp, K. J. M.; van Zanden, M. N. A.; Hiemstra,H.; Speckamp, W. N. J. Org. Chem. 1994, 59, 1993; Seijas et al,Tetrahedron, 1992, 48(9), 1637; Nagashima, H.; Wakamatsu, H.; Ozaki, N.;Ishii, T.; Watanabe, M.; Tajima, T.; Itoh, K. J. Org. Chem. 1992, 57,1682; Hayes, T. K.; Villani, R.; Weinreb, S. M. J. Am. Chem. Soc. 1988,110, 5533; Hirao et al, Syn. Lett., 1990, 217; and Hirao et al, J.Synth. Org. Chem. (Japan), 1994, 52(3), 197; Iqbal, J; Bhatia, B.;Nayyar, N. K. Chem. Rev., 94, 519 (1994); Asscher, M., Vofsi, D. J.Chem. Soc. 1963, 1887; and van de Kuil et al, Chem. Mater., 1994, 6,1675). In these reactions, a catalytic amount of transition metalcompound acts as a carrier of the halogen atom in a redox process.

Initially, the transition metal species, M_(t) ^(n), abstracts halogenatom X from the organic halide, R—X, to form the oxidized species, M_(t)^(n+1)X, and the carbon-centered radical R⁻. In the subsequent step, theradical, R⁻, reacts with alkene, M, with the formation of theintermediate radical species, R—M⁻. The reaction between M_(t) ^(n+1)Xand R—M results in the target product, R—M—X, and regenerates thereduced transition metal species, M_(t) ^(n), which further reacts withR—X and promotes a new redox process.

The high efficiency of transition metal-catalyzed atom transferreactions in producing the target product, R—M—X, in good to excellentyields (often >90%) may suggest that the presence of an M_(t) ^(n)/M_(t)^(n+1) cycle-based redox process can effectively compete with thebimolecular termination reactions between radicals (see Curran,Synthesis, in Free Radicals in Synthesis and Biology, and inComprehensive Organic Synthesis, supra). However, the mere presence of atransition metal compound does not ensure success in telomerization orpolymerization, even in the presence of initiators capable of donating aradical atom or group. For example, Asscher et al (J. Chem. Soc., supra)reported that copper chloride completely suppresses telomerization.

Furthermore, even where a transition metal compound is present andtelomerization or polymerization occurs, it is difficult to control themolecular weight and the polydispersity (molecular weight distribution)of polymers produced by radical polymerization. Thus, it is oftendifficult to achieve a highly uniform and well-defined product. It isalso often difficult to control radical polymerization processes withthe degree of certainty necessary in specialized applications, such asin the preparation of end functional polymers, block copolymers, star(co)polymers, etc. Further, although several initiating systems havebeen reported for “living”/controlled polymerization, no general pathwayor process for “living”/controlled polymerization has been discovered.

Copolymerization of electron-donor type monomers (unsaturatedhydrocarbons, vinyl ethers, etc.) with electron acceptor type monomers;(acrylates, methacrylates, unsaturated nitrites, unsaturated ketones,etc.) in the presence of monomer complexing agents (ZnCl₂, Et₃Al₂Cl₃,etc.) yield highly, if not strictly alternating copolymers (Hirooka etal, J. Polym. Sci. Part B, 5, 47 (1967); Furukawa et al, Rubber Chem.Technol., 51(3), 601 (1979)). The copolymerization succeeded, however,only if the polar monomer was significantly complexed by the Lewis acid.Further, the copolymerization was often initiated spontaneously, thusyielding very high molecular weight products having broadpolydispersities. The mechanism of this reaction is controversial andthere are suggestions that it is due to a complex (Hirai, J. Polym. Sci.Macromol. Rev., 11, 47 (1976)) or to enhanced cross-propagation rates(Bamford et al, J. Polym. Sci. Polym. Lett. Ed., 19, 229 (1981) and J.Chem. Soc. Faraday Trans. 1, 78, 2497 (1982)).

In the radical copolymerization of isobutylene (IB) and acrylic esters,the resulting copolymers contain at most 20-30% of IB and have lowmolecular weights because of degradative chain transfer of IB (U.S. Pat.Nos. 2,411,599 and 2,531,196; and Mashita et al, Polymer, 36, 2973(1995).

Conjugated monomers such acrylic esters and acrylonitrile react withdonor monomers such as propylene, isobutylene, styrene in the presenceof alkylaluminum halide to give 1:1 alternating copolymers (Hirooka etal, J. Polym. Sci. Polym. Chem., 11, 1281 (1973)). The alternatingcopolymer was obtained when [Lewis acid]₀/[acrylic esters]₀=0.9 and[IB]₀>[acrylic esters]₀. The copolymer of IB and methyl acrylate (MA)obtained by using ethyl aluminum sesquichloride and 2-methyl pentanoylperoxide as an initiating system is highly alternating, with either low(Kuntz et al, J. Polym. Sci. Polym. Chem., 16, 1747!(1978)) or high(60%) isotacticity in the presence of EtAlCl₂ (10 molar % relative toMA) at 50° C. (Florjanczyk et al, Makromol. Chem., 183, 1081 (1982)).

Recently, alkyl boron halide was found to have a much higher activitythan alkyl aluminum halide in alternating copolymerization of IB andacrylic esters (Mashita et al, Polymer, 36, 2983 (1995)). Thepolymerization rate has a maximum at about −50° C. and decreasedsignificantly above 0° C. The copolymerization is controlled by O₂ interms of both rate and molecular weight. The alternating copolymer wasobtained when [IB]₀>[Acrylic esters]₀. Stereoregularity was consideredto be nearly random. The copolymer is an elastomer of high tensilestrength and high thermal decomposition temperature. The oil resistanceis very good, especially at elevated temperatures, and the hydrolysisresistance was excellent compared to that of the correspondingpoly(acrylic ester)s (Mashita et al, supra).

Dendrimers have recently received much attention as materials with novelphysical properties (D. A. Tomalia, A. M. Naylor, W. A. G. III, Angew.Chem., Int. Ed. Engl. 29, 138 (1990); J. M. J. Frechet, Science 263,1710 (1994)). These polymers have viscosities lower than linear analogsof similar molecular weight, and the resulting macromolecules can behighly functionalized. However, the synthesis of dendrimers is nottrivial and requires multiple steps, thus generally precluding theircommercial development.

Polymers consisting of hyperbranched phenylenes (O. W. Webster, Y. H.Kim, J. Am. Chem. Soc. 112, 4592 (1990) and Macromolecules 25, 5561(1992)), aromatic esters (J. M. J. Frechet, C. J. Hawker, R. Lee, J. Am.Chem. Soc., 113, 4583 (1991)), aliphatic esters (A. Hult, E. Malmstrom,M. Johansson, J. Polym. Sci. Polym. Ed. 31, 619 (1993)), siloxanes (L.J. Mathias, T. W. Carothers, J. Am. Chem. Soc. 113, 4043 (1991)), amines(M. Suzuki, A. Li, T. Saegusa, Macromolecules 25, 7071 (1992)) andliquid crystals (V. Percec, M. Kawasumi, Macromolecules 25, 3843 (1992))have been synthesized in the past few years.

Recently, a method has been described by which functionalized vinylmonomers could be used as monomers for the synthesis of hyperbranchedpolymers by a cationic polymerization (J. M. J. Frechet, et al., Science269, 1080 (1995)). The monomer satisfies the AB₂ requirements forformation of hyperbranched polymers by the vinyl group acting as thedifunctional B group, and an additional alkyl halide functional group asthe A group. By activation of the A group with a Lewis acid,polymerization through the double bond can occur. In this method,3-(1-chloroethyl)-ethenylbenzene was used as a monomer and wascationically polymerized in the presence of SnCl₄.

A need is strongly felt for a radical polymerization process whichprovides (co)polymers having a predictable molecular weight and acontrolled molecular weight. distribution (“polydispersity”). A furtherneed is strongly felt for a radical polymerization process which issufficiently flexible to provide a wide variety of products, but whichcan be controlled to the degree necessary to provide highly uniformproducts with a controlled structure (i.e., controllable topology,composition, stereoregularity, etc.), many of which are suitable forhighly specialized uses (such as thermoplastic elastomers,end-functional polymers for chain-extended polyurethanes, polyesters andpolyamides, dispersants for polymer blends, etc.).

SUMMARY OF THE INVENTION

Accordingly, one object of the present invention is to provide a novelmethod for radical polymerization of alkenes based on atom transferradical polymerization (ATRP), which provides a level of molecularcontrol over the polymerization process presently obtainable only byliving ionic or metathesis polymerization, and which leads to moreuniform and more highly controllable products.

A further object of the present invention is to provide novelimprovements to a method for radical polymerization of alkenes based onatom transfer radical polymerization (ATRP), which increases initiatorefficiencies and process yields, and improves product properties.

A further object of the present invention is to provide a broad varietyof novel (co)polymers having more uniform properties than those obtainedby conventional radical polymerization.

A further object of the present invention is to provide novel(co)polymers having new and useful structures and properties.

A further object of the present invention is to provide a process forradically polymerizing a monomer which is adaptable to use with existingequipment.

A further object of the present invention is to provide a method forproducing a (co)polymer which relies on readily available startingmaterials and catalysts.

A further object of the present invention is to provide (co)polymershaving a wide variety of compositions (e.g., random, alternating,tapered, end-functional, telechelic, etc.) and topologies (block, graft,star, dendritic or hyperbranched, comb, etc.) having controlled, uniformand/or well-defined structures and properties.

A further object of the present invention is to provide a novel methodfor radically polymerizing a monomer which can use water as a solventand which provides novel water-soluble (co)polymers.

A further object of the present invention is to provide novel(co)polymers which are useful as gels and hydrogels, and to providenovel methods for making such (co)polymers.

A further object of the present invention is to provide novel(co)polymers which are useful in a wide variety of applications (forexample, as adhesives, asphalt modifiers, in contact lenses, asdetergents, diagnostic agents and supports therefor, dispersants,emulsifiers, elastomers, engineering resins, viscosity index improvers,in ink and imaging compositions, as leather and cement modifiers,lubricants and/or surfactants, with paints and coatings, as paperadditives and coating agents, as an intermediate for preparing largermacromolecules such as polyurethanes, as resin modifiers, in textiles,as water treatment chemicals, in the chemical and chemical wasteprocessing, composite fabrication, cosmetics, hair products, personalcare products in plastics compounding as, for example, an antistaticagent, in food and beverage packaging, pharmaceuticals [as, e.g., abulking agent, “slow release” or sustained release compounding agent],in rubber, and as a preservative).

These and other objects of the present invention, which will be readilyunderstood in the context of the following detailed description of thepreferred embodiments, have been provided in part by a novel controlledprocess of atom (or group) radical transfer polymerization, comprisingthe steps of:

polymerizing one or more radically polymerizable monomers in thepresence of an initiating system comprising:

an initiator having a radically transferable atom or group,

a transition metal compound which participates in a reversible redoxcycle (i.e., with the initiator),

an amount of the redox conjugate of the transition metal compoundsufficient to deactivate at least some initially-formed radicals, and

any N—, O—, P—or S— containing ligand which coordinates in a σ-bond orany carbon-containing ligand which coordinates in a π-bond to thetransition metal, or any carbon-containing ligand which coordinates in acarbon-transition metal σ-bond but which does not form a carbon-carbonbond with said monomer under the polymerizing conditions, to form a(co)polymer, and

isolating the formed (co)polymer; and, in part, by novel (co)polymersprepared by atom (or group) radical transfer polymerization.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a variety of different polymer topologies, compositions andfunctionalizations which can be achieved by the present invention, butto which the present invention is not restricted;

FIG. 2 shows a comparison of mechanisms, exemplary kinetic parametersand product properties of conventional radical polymerization with thepresent “living”/controlled radical polymerization;

FIGS. 3A-B are plots of molecular weight (M_(n)) and polydispersities(M_(w)/M_(n)). vs. time (FIG. 3A) and of the instantaneous compositionof the copolymer (F_(inst)) vs. chain length (FIG. 3B) for the gradientcopolymerization of Example 16 below;

FIGS. 4A-B are plots of molecular weight (M_(n)) and polydispersities(M_(w)/M_(n)) vs. time (FIG. 4A) and of the instantaneous composition ofthe copolymer (F_(inst)) vs. chain length (FIG. 4B) for the gradientcopolymerization of Example 17 below;

FIGS. 5A-B are plots of molecular weight (M_(n)) and polydispersities(M_(w)/M_(n)) vs. time (FIG. 5A) and of the instantaneous composition ofthe copolymer (F_(inst)) vs. chain length (FIG. 5B) for the gradientcopolymerization of Example 18 below;

FIGS. 6A-B are plots of molecular weight (M_(n)) and polydispersities(M_(w)/M_(n)) vs. time (FIG. 6A) and of the instantaneous composition ofthe copolymer (F_(inst)) vs. chain length (FIG. 6B) for the gradientcopolymerization of Example 19 below;

FIGS. 7A-B are plots of molecular weight (M_(n)) and polydispersities(M_(w)/M_(n)) vs. time (FIG. 7A) and of the instantaneous composition ofthe copolymer (F_(inst)) vs. chain length (FIG. 7B) for a gradientcopolymerization described in Example 20 below;

FIGS. 8A-B are plots of molecular weight (M_(n)) and polydispersities(M_(w)/M_(n)) vs. time (FIG. 8A) and of the instantaneous composition ofthe copolymer (F_(inst)) vs. chain length (FIG. 8B) for a gradientcopolymerization described in Example 20 below; and

FIGS. 9A-B are plots of molecular weight (M_(n)) and polydispersities(M_(w)/M_(n)) vs. time (FIG. 9A) and of the instantaneous composition ofthe copolymer (F_(inst)) vs. chain length (FIG. 9B) for a gradientcopolymerization described in Example 20below.

FIG. 10 is a plot of the fraction of monomer A and monomer B in thecopolymer along the polymer chain length of one embodiment of a gradientcopolymer.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

It has been conceptualized that if (1) the organic halide R—M_(i)—Xresulting from an ATRA reaction is sufficiently reactive towards thetransition metal M_(t) ^(n) and (2) the alkene monomer is in excess, anumber or sequence of atom transfer radical additions (i.e., a possible“living”/controlled radical polymerization) may occur. By analogy toATRA, the present new process of radical polymerization has been termed“atom (or group) transfer radical polymerization” (or “ATRP”), whichdescribes the involvement of (1) the atom or group transfer pathway and(2) a radical intermediate.

Living/controlled polymerization (i.e., when chain breaking reactionssuch as transfer and termination are substantially absent) enablescontrol of various parameters of macromolecular structure such asmolecular weight, molecular weight distribution and terminalfunctionalities. It also allows the preparation of various copolymers,including block and star copolymers. Living/controlled radicalpolymerization requires a low stationary concentration of radicals, inequilibrium with various dormant species.

In the context of the present invention, the term “controlled” refers tothe ability to produce a product having one or more properties which arereasonably close to their predicted value (presuming a particularinitiator efficiency). For example, if one assumes 100% initiatorefficiency, the molar ratio of catalyst to monomer leads to a particularpredicted molecular weight. The polymerization is said to be“controlled” if the resulting number average molecular weight(M_(w)(act)) is reasonably close to the predicted number averagemolecular weight (M_(w)(pred)); e.g., within an order of magnitude,preferably within a factor of four, more preferably within a factor ofthree and most preferably within a factor of two (i.e., M_(w)(act) is inthe range of from (0.1)×M_(w)(pred) to 10×M_(w)(pred), preferably from(0.25)×M_(w)(pred) to 4×M_(w)(pred), more preferably from(0.5)×M_(w)(pred) to 2 M_(w)(pred), and most preferably from(0.8)×M_(w)(pred) to 1.2×M_(w)(pred)).

Similarly, one can “control” the polydispersity by ensuring that therate of deactivation is the same or greater than the initial rate ofpropagation. However, the importance of the relativedeactivation/propagation rates decreases proportionally with increasingpolymer chain length and/or increasing predicted molecular weight ordegree of polymerization.

The present invention describes use of novel initiating systems leadingto living/controlled radical polymerization. The initiation system isbased on the reversible formation of growing radicals in a redoxreaction between various transition metal compounds and an initiator,exemplified by (but not limited to) alkyl halides, aralkyl halides orhaloalkyl esters. Using 1-phenylethyl chloride (1-PECl) as a modelinitiator, CuCl as a model catalyst and bipyridine (Bpy) as a modelligand, a “living” radical bulk polymerization of styrene at 130° C.affords the predicted molecular weight up to M_(n)≈10⁵ with a narrowmolecular weight distribution (e.g., M_(w)/M_(n)<1.5).

A key factor in the present invention is to achieve rapid exchangebetween growing radicals present at low stationary concentrations (inthe range of from 10⁻⁹ mol/L to 10⁻⁵ mol/L, preferably 10⁻⁸ mol/L to10⁻⁵ mol/L) and dormant chains present at higher concentrations(typically in the range 10⁻⁴ mol/L to 3 mol/L, preferably 10⁻² mol/L to10⁻¹ mol/L). It may be desirable to “match” theinitiator/catalyst/ligand system and monomer(s) such that theseconcentration ranges are achieved.

Although these concentration ranges are not essential to conductingpolymerization, certain disadvantageous effects may result if theconcentration ranges are exceeded. For example, if the concentration ofgrowing radicals exceeds 10⁻⁵ mol/L, there may be too many activespecies in the reaction, which may lead to an undesirable increase inthe rate of side reactions (e.g., radical-radical quenching, radicalabstraction from species other than the catalyst system, etc.). If theconcentration of growing radicals is less than 10⁻⁹ mol/L, the rate maybe undesirably slow. However, these considerations are based on anassumption that only free radicals are present in the reaction system.It is believed that some radicals are in a caged form, the reactivitiesof which, especially in termination-deactivation reactions, may differfrom those of uncaged free radicals.

Similarly, if the concentration of dormant chains is less than 10⁻⁴mol/L, the molecular weight of the product polymer may increasedramatically, thus leading to a potential loss of control of themolecular weight and the polydispersity of the product. On the otherhand, if the concentration of dormant species is greater than 3 mol/L,the molecular weight of the product may become too small, and theproperties of the product may more closely resemble the properties ofoligomers. (However, oligomeric products are useful, and are intended tobe included within the scope of the invention.)

For example, in bulk, a concentration of dormant chains of about 10⁻²mol/L provides product having a molecular weight of about 100,000 g/mol.On the other hand, a concentration of dormant chains exceeding 1 M leadsto formation of (roughly) less than decameric products, and aconcentration of about 3 M leads to formation of (predominantly)trimers.

In application Ser. No. 08/414,415, filed Mar. 31, 1995, now U.S. Pat.No. 5,763,548 (incorporated herein by reference in its entirety), amethod of preparing a (co)polymer by ATRP is disclosed which comprises:

polymerizing one or more radically polymerizable monomers in thepresence of an initiator having a radically transferable atom or group,a transition metal compound and a ligand to form a (co)polymer, thetransition metal compound being capable of participating in a redoxcycle with the initiator and a dormant polymer chain, and the ligandbeing any N-, O-, P- or S- containing compound which can coordinate in aσ-bond to the transition metal or any carbon-containing compound whichcan coordinate in a π-bond to the transition metal, such that directbonds between the transition metal and growing polymer radicals are notformed, and

isolating the formed (co)polymer.

The present invention includes the following:.

(1) an ATRP process in which the improvement comprises polymerizing,inthe presence of an amount of the corresponding reduced or oxidizedtransition metal compound which deactivates at least some free radicals;

(2) an ATRP process in which the improvement comprises polymerizing in ahomogeneous system or in the presence of a solubilizedinitiating/catalytic system;

(3) end-functional, site-specific functional and telechelic homopolymersand copolymers (see FIG. 1);

(4) block, random, graft, alternating and tapered (or“gradient”),copolymers which may have certain properties or a certainstructure (e.g., a copolymer of alternating donor and acceptor monomers,such as the radical copolymer of isobutylene and a (meth)acrylate ester;see FIG. 1);

(5) star, comb and dendritic (or “hyperbranched”) polymers andcopolymers (see FIG. 1);

(6) end-functional and/or multi-functional hyperbranched polymers (seeFIG. 1);

(7) cross-linked polymers and gels;

(8) water-soluble polymers and new hydrogels (e.g., copolymers preparedby radical polymerization, comprising a water-soluble backbone andwell-defined hydrophobic (co)polymer chains grafted thereonto); and

(9) an ATRP process using water as a medium.

In one embodiment, the present invention concerns improved methods ofatom or group transfer radical polymerization, in which a proportion(e.g., 0.1-99.9 mol %, preferably 0.2-10 mol % and more preferably 0.5-5mol %) of the transition metal catalyst is in an oxidized or reducedstate, relative to the bulk of the transition metal catalyst. Theoxidized or reduced transition metal catalyst is the redox conjugate ofthe primary transition metal catalyst; i.e., for the M_(t) ^(n+):M_(t)^(m+) redox cycle, 90-99.9 mol % of transition metal M_(t) atoms may bein the n⁺ oxidation state and 0.1-10 mol % of transition metal M_(t)atoms may be in the m⁺ oxidation state. The term “redox conjugate” thusrefers to the corresponding oxidized or reduced form of the transitionmetal catalyst. Oxidation states n and m are attained by transitionmetal M_(t) as a consequence of conducting ATRP.

The present Inventors have found that an amount of redox conjugatesufficient to deactivate at least some of the radicals which may form atthe beginning of polymerization (e.g., the product of self-initiation orof addition of an initiator radical or growing polymer chain radical toa monomer) greatly improves the polydispersity and control of themolecular weight of the product. The effects and importance of rates ofexchange between growing species of different reactivities and differentlifetimes, relative to the rate of propagation, has not beensufficiently explored in previous work by others, but has been found bythe present Inventors to have a tremendous effect on polydispersity andcontrol of molecular weight in living/controlled polymerizations.

As is shown in FIG. 2, both conventional and controlled polymerizationscomprise the reactions of initiating radicals with monomer at a rateconstant k_(i), propagation of growing chains with monomer at a rateconstant k_(p), and termination by coupling and/or disproportionationwith an average rate constant k_(t). In both systems, the concentrationof radicals at any given moment (the momentary concentration of growingradicals, or [P]₀) is relatively low, about 10⁻⁷ mol/L or less.

However, in conventional radical polymerization, initiator is consumedvery slowly (k_(dec)≈10^(−5±1)s⁻¹). Furthermore, in conventional radicalpolymerization, the initiator half-lifetime is generally in the range ofhours, meaning that a significant proportion of initiator remainsunreacted, even after monomer is completely consumed.

By contrast, in controlled polymerization systems, the initiator islargely consumed at low monomer conversion (e.g., 90% or more ofinitiator may be consumed at less than 10% monomer conversion).

In ATRP, growing radicals are in dynamic equilibrium with dormantcovalent species. Covalent R—X and P—X bonds (initiator and dormantpolymer, respectively) are homolytically cleaved to form initiating (R⁻)or propagating (P⁻) radicals and corresponding counter-radicals X⁻. Theequilibrium position defines the momentary concentration of growingradicals, the polymerization rate and the contribution of termination.The dynamics of equilibration also affects polydispersity and the,molecular weight of the polymer as a function of monomer conversion.

A model study has been performed on polymerization of methyl acrylate at100° C., based on numerical integration using a discrete Galerkin method(Predici program). In this study, the rate constants of propagation(k_(p)=7×10³ mol⁻¹ L s⁻¹) and termination (k_(t)=10⁷ mol⁻¹ L s⁻¹) werebased on data available from published literature. The rate constants ofactivation and deactivation for the initiating system 1-phenylethylchloride/CuCl/2,2′-bipyridyl were then varied over five orders ofmagnitude, maintaining an equilibrium constant value K=10⁻⁸. As a resultof this model study, it was found that addition of 1% Cu(II) (redoxconjugate) dramatically improves the polydispersity of, and providespredictable molecular weights for, the obtained (co)polymer products.

The equilibrium constant (i.e., the ratio of the activation rateconstant k_(a) to deactivation rate constant k_(d)) can be estimatedfrom known concentrations of radicals, covalent alkyl halides, activatorand deactivator according to the equation:

K=k_(a)/k_(d)=([Cu^(II)][P⁻])/([Cu^(I)][I]₀)

Simulations were performed for bulk polymerization of methyl acrylate([M]₀=11 M) or styrene ([M]₀=9 M) using an initiating system containing1-PECl ([I]₀=0.1 M), a 2,2′-bipyridyl)CuCl complex ([Cu^(I)]₀=0.1 M) andeither 1% or 0% Cu^(II) as an initial deactivator ([Cu^(II)]₀=0.001 M or0 M). The stationary concentration of radicals is approximately 10⁻⁷ M,leading to the result that K is approximately 10^(−8.)

After initiation in the system without Cu(II), the momentaryconcentration of radicals is reduced from 8×10⁻⁷ M at 10% conversion to3.3×10⁻⁷ M at 50% conversion and 1.6×10⁻⁷ M at 90% conversion. At thesame time, the concentration of deactivator (Cu^(II)) increases from1.2×10⁻⁴ M at 10% conversion to 3×10⁻⁴ M at 50% conversion and 6×10⁻⁴ Mat 90% conversion. The concentration of deactivator corresponds to theconcentration of terminated chains, which at 90% monomer conversion, isonly about 0.6% of all chains generated from the initiator.

In the presence of 1% deactivator (redox conjugate), a nearly constantconcentration of growing radicals is predicted. The momentaryconcentration of polymer radicals is much more constant in the presenceof 1% deactivator, going from 0.98×10⁻⁷ M at 10% conversion to 0.94×10⁻⁷M at 50% conversion and 0.86×10⁻⁷ M at 90% conversion. At the same time,the deactivator concentration increases from 1.01×10⁻⁴ M at 10%conversion to 1.05×10⁻⁴ M at 50% conversion and 1.15×10⁻³ M at 90%conversion. The concentration of terminated chains corresponds to theincrease in concentration of deactivator although the initialconcentration, which translates to 0.15% of all chains being terminatedat 90% conversion.

The dynamics of exchange has no effect on kinetics in the studied rangeof k_(a) and k_(d) values. However, dynamics has a tremendous effect onmolecular weights and polydispersities.

In the absence of deactivator in the model systems studied, a degree ofpolymerization (DP_(n)) of about 90 is expected. However, ifdeactivation is slow, very high molecular weights are initiallyobserved. As conversion increases, the molecular weights slowly begin tocoincide with predicted values. The initial discrepancy has a tremendouseffect on polydispersities, as will be discussed below.

If deactivation is sufficiently fast (in the model system, about 10⁷mol⁻¹ L s⁻¹), the predicted and observed molecular weights are insubstantial agreement from the beginning of polymerization. However,when deactivation is slow, the initial DP is substantially higher thanpredicted (DP=60 when k_(d)=10⁶ M⁻¹ s⁻¹, and DP=630 when k_(d)=10⁵ M⁻¹s⁻¹). Thus, initial values of DP can be predicted by the ratio ofpropagation to de activation rates by the equation:

DP=R_(p)/R_(d)=k_(p)[M]₀[P⁻]/k_(d)[Cu^(II)]₀[P⁻]

Regardless of the rate of deactivation, however, initialpolydispersities are much higher than those predicted for a Poissondistribution. However, if deactivation is sufficiently fast, at completeconversion, vary narrow polydispersities (M_(w)/M_(n)) are observed(e.g., less than 1.1). On the other hand, if the rate of deactivation isabout the same as the rate of termination (in the model case, about 10⁷M⁻¹ s⁻¹), then the polydispersity at complete conversion is about 1.5.When deactivation is about three times slower, the polydispersity atcomplete conversion is about 2.5.

However, in the presence of 1% deactivator, a deactivation rate which isabout the same as the termination rate results in a polydispersity closeto ideal (<1.1) at complete conversion although initially, it is ratherhigh (about 2), decreasing to about 1.5 at 25% conversion and <1.2 at75% conversion. Where deactivation is slower (k_(d)=10⁶) the finalpolydispersity is 1.7. A small quantity of deactivator (redox conjugate)is sufficient to trap or quench the free radicals formed duringpolymerization. A large excess of redox conjugate is not necessary,although it does not have an adverse,or continuous effect on thepolymerization rate.

It is noted that an average termination rate constant k_(t)=10⁷ M⁻¹ s⁻¹was used. However, the actual termination rate constant strongly dependson chain length. For monomeric radicals, it can be as high at 10⁹M⁻¹s⁻¹, but for very long chains, it can be as low as 10² M⁻¹ s⁻¹. Onemajor difference between controlled polymerization and conventionalradical polymerization is that nearly all chains have similar chainlength in controlled polymerization, whereas new radicals arecontinuously generated in conventional radical polymerization.Therefore, at substantial conversion, long chain radicals do not reactwith one another, but rather, with newly generated low molecular massradicals in conventional polymerization. In controlled systems, bycontrast, after a certain chain length has been achieved, the reactionmixture becomes more viscous, and the actual rate constant oftermination may dramatically drop, thus improving control ofpolymerization to a degree greater than one would predict prior to thepresent invention.

The addition of a redox conjugate to ATRP also increases control ofmolecular weight and polydispersities by scavenging radicals formed byother processes, such as thermal self-initiation of monomer. Forexample, in the model systems studied, CuCl₂ acts as an inhibitor ofpolymerization, and scavenges polymer chains at an early stage,preventing formation of a high molecular weight polymer which may beformed by thermal self-initiation.

It has been observed by the present Inventors that the rate ofpolymerization is not affected in a linear fashion by the amount orconcentration of the deactivating agent (redox conjugate). For example,the presence of 5 mol % of redox conjugate may be expected to decreasethe polymerization rate 10-fold relative to 0.5 mol % of redoxconjugate. However, 5 mol % of redox conjugate actually decreases thepolymerization rate by a significantly smaller amount than 10-foldrelative to 0.5 mol % of redox conjugate. Although a precise explanationfor this phenomenon is not yet available, it is believed that manyradicals generated by the present ATRP initiator/transition metalcompound/ligand system may be protected by a solvent/monomer “cage.”Thus, the presence of more than 10 mol % of redox conjugate does notadversely affect polymerization by ATRP, although it may slow thepolymerization rate to a small extent.

Experimental observations also support the idea that large amounts ofredox conjugate are not harmful to polymerization, a result which issurprising in view of observations that redox conjugates adverselyaffect ATRA. For example, in the heterogeneous ATRP of acrylates usingcopper(I) chloride, the color of the catalyst changes from red (Cu^(I))to green (Cu^(II)). However, the apparent rate constant ofpolymerization is essentially constant, or at least does notsignificantly decrease.

As described above, the redox conjugate is present in an amountsufficient to deactivate at least some of the initially-formedinitiator-monomer adduct radicals, thermal self-initiation radicals andsubsequently-formed growing polymer radicals. One key to achievingnarrow polydispersities is to control the polymerization reactionparameters such that the rate of radical deactivation is roughly thesame as or greater than the rate of propagation.

In one embodiment, the improvement to the method comprises adding thetransition metal redox conjugate to the reaction mixture prior topolymerizing. Alternatively, when the transition metal compound iscommercially available as a mixture with its redox conjugate (e.g., manycommercially available Cu(I) salts contain 1-2 mol % of Cu(II)), theimproved process comprises adding the transition metal compound to thepolymerization reaction mixture without purification.

In an alternative embodiment, the improved ATRP method comprisesexposing the transition metal compound to oxygen for a length of timeprior to polymerizing the monomer(s). In preferred embodiments, thesource of oxygen is air, and the length of time is sufficient to providefrom 0.1 to 10 mol % of the redox conjugate of the transition metalcompound. This embodiment is particularly suitable when the transitionmetal is a Cu(I) compound, such as CuCl or CuBr.

One may also conduct a “reverse” ATRP, in which the transition metalcompound is in its oxidized state, and the polymerization is initiatedby, for example, a radical initiator such as azobis(isobutyronitrile)(“AIBN”), a peroxide such as benzoyl peroxide (BPO) or a peroxy acidsuch as peroxyacetic acid or peroxybenzoic acid. The radical initiatoris believed to initiate “reverse” ATRP in the following fashion:

I—I→2 I⁻

I⁻+M_(t) ^(n+1)X_(n)⇄I—X+M_(t) ^(n)X_(n−1)

I⁻+M→I—M⁻

I—M⁻+M_(t) ^(n+1)X_(n)⇄I—M—X+M_(t) ^(n)X_(n−1)

I—M⁻+n M→I—M_(n+1) ⁻

I—M_(n+1) ⁻+M_(t) ^(n+1)X_(n)⇄I—M_(n+1)—X+M_(t) ^(n)X_(n−1)

where “I” is the initiator, M_(t) ^(n)X_(n−1) is the transition metalcompound, M is the monomer, and I—M—X and t participate in“conventional” or “forward” ATRP in the manner described above.

After the polymerizing step is complete, the formed polymer is isolated.The isolating step of the present process is conducted by knownprocedures, and may comprise evaporating any residual monomer and/orsolvent, precipitating in a suitable solvent, filtering or centrifugingthe precipitated polymer, washing the polymer and drying the washedpolymer. Transition metal compounds may be removed by passing a mixturecontaining them through a column or pad of alumina, silica and/or clay.Alternatively, transition metal compounds may be oxidized (if necessary)and retained in the (co)polymer as a stabilizer.

Precipitation can be typically conducted using a suitable C₅-C₈-alkaneor C₅-C₈-cycloalkane solvent, such as pentane, hexane, heptane,cyclohexane or mineral spirits, or using a C₁-C₆-alcohol, such asmethanol, ethanol or isopropanol, or any mixture of suitable solvents.Preferably, the solvent for precipitating is water, hexane, mixtures ofhexanes, or methanol.

The precipitated (co)polymer can be filtered by gravity or by vacuumfiltration, in accordance with known methods (e.g., using a Büchnerfunnel and an aspirator). Alternatively, the precipitated (co)polymercan be centrifuged, and the supernatant liquid decanted to isolate the(co)polymer. The (co)polymer can then be can be washed with the solventused to precipitate the polymer, if desired. The steps of precipitatingand/or centrifuging, filtering and washing may be repeated, as desired.

Once isolated, the (co)polymer may be dried by drawing air through the(co)polymer, by vacuum, etc., in accordance with known methods(preferably by vacuum). The present (co)polymer may be analyzed and/orcharacterized by size exclusion chromatography, NMR spectroscopy, etc.,in accordance with known procedures.

The various initiating systems of the present invention work for anyradically polymerizable alkene, including (meth)acrylates, styrenes anddienes. It also provides various controlled copolymers, including block,random, alternating, gradient, star, graft or “comb,” and hyperbranchedand/or dendritic (co)polymers. (In the present application,“(co)polymer” refers to a homopolymer, copolymer, or mixture thereof.)Similar systems have been used previously in organic synthesis, but havenot been used for the preparation of well-defined macromolecularcompounds.

In the present invention, any radically polymerizable alkene can serveas a :monomer for polymerization. However, monomers suitable forpolymerization in the present method include those of the formula:

wherein R¹ and R² are independently selected from the group consistingof H, halogen, CN, straight or branched alkyl of from 1 to 20 carbonatoms (preferably from 1 to 6 carbon atoms, more preferably from 1 to 4carbon atoms) which may be substituted with from 1 to (2n+1) halogenatoms where n is the number of carbon atoms of the alkyl group (e.g.CF₃), α,β-unsaturated straight or branched alkenyl or alkynyl of 2 to 10carbon atoms (preferably from 2 to 6 carbon atoms, more preferably from2 to 4 carbon atoms) which may be substituted with from 1 to (2n−1)halogen atoms (preferably chlorine) where n is the number of carbonatoms of the alkyl group (e.g. CH₂═CCl—), C₃-C₈ cycloalkyl which may besubstituted with from 1 to (2n−1) halogen atoms (preferably chlorine)where n is the number of carbon atoms of the cycloalkyl group, C(═Y)R⁵,C(═Y)NR⁶R⁷, YC(═Y)R⁵, SOR⁵, SO₂R⁵, OSO₂R⁵, NR⁸SO₂R⁵, PR⁵ ₂, P(═Y)R⁵ ₂,YPR⁵ ₂, YP(═Y)R⁵ ₂, NR⁸ ₂ which may be quaternized with an additional R⁸group, aryl and heterocyclyl; where Y may be NR⁸, S or O(preferably O);R⁵ is alkyl of from 1 to 20 carbon atoms, alkylthio of from 1 to 20carbon atoms, OR²⁴ (where R²⁴ is H or an alkali metal), alkoxy of from 1to 20 carbon atoms, aryloxy or heterocyclyloxy; R⁶ and R⁷ areindependently H or alkyl of from 1 to 20 carbon atoms, or R⁶ and R⁷ maybe joined together to form an alkylene group of from 2 to 7 (preferably2 to 5) carbon atoms; thus forming a 3- to 8-membered (preferably 3- to6-membered) ring, and R⁸ is H, straight or branched C₁-C₂₀ alkyl oraryl;

R³ and R⁴ are independently selected from the group consisting of H,halogen (preferably fluorine or chlorine), C₁-C₆ (preferably C₁) alkyland COOR⁹ (where R⁹ is H, an alkali metal, or a C₁-C₆ alkyl group), or

R¹ and R³ may be joined to form a group of the formula (CH₂)_(n), (whichmay be substituted with from 1 to 2n′ halogen atoms or C₁-C₄ alkylgroups) or C(═O)—Y—C(═O), where n′ is from 2 to 6 (preferably 3 or 4)and Y is as defined above; and

at least two of R¹, R², R³ and R⁴ are H or halogen.

In the context of the present application, the terms “alkyl”, “alkenyl”and “alkynyl” refer to straight-chain or branched groups (except for C₁and C₂ groups). “Alkenyl” and “alkynyl” groups may have sites ofunsaturation at any adjacent carbon atom position(s) as long as thecarbon atoms remain tetravalent, but α,β- or terminal (i.e., at the ω-and (ω−1)-positions) are preferred.

Furthermore, in the present application, “aryl” refers to phenyl,naphthyl, phenanthryl, phenalenyl, anthracenyl, triphenylenyl,fluoranthenyl, pyrenyl, pentacenyl, chrysenyl, naphthacenyl, hexaphenyl,picenyl and perylenyl (preferably phenyl and naphthyl) in which eachhydrogen atom may be replaced with halogen, alkyl of from 1 to 20 carbonatoms (preferably from 1 to 6 carbon atoms and more preferably methyl)in which each of the hydrogen atoms may be independently replaced by anX group as defined above (e.g., a halide, preferably a chloride or abromide), alkenyl or alkynyl of from 2 to 20 carbon atoms in which eachof the hydrogen atoms may be independently replaced by an X group asdefined above (e.g., a halide, preferably a chloride or a bromide),alkoxy of from 1 to 6 carbon atoms, alkylthio of from 1 to 6 carbonatoms, C₃-C₈ cycloalkyl in which each of the hydrogen atoms may beindependently replaced by an X group as defined above (e.g., a halide,preferably a chloride or a bromide), phenyl, NH₂ or C₁-C₆-alkylamino orC₁-C₆-dialkylamino which may be quaternized with an R⁸ group, COR⁵,OC(═O)R⁵, SOR⁵, SO₂R⁵, OSO₂R⁵, PR⁵ ₂, POR⁵ ₂ and phenyl which may besubstituted with from 1 to 5 halogen atoms and/or C₁-C₄ alkyl groups.(This definition of “aryl” also applies to the aryl groups in “aryloxy”and “aralkyl.”) Thus, phenyl may be substituted from 1 to 5 times andnaphthyl may be substituted from 1 to 7 times (preferably, any arylgroup, if substituted, is substituted from 1 to 3 times) with one ormore of the above substituents. More preferably, “aryl” refers tophenyl, naphthyl, phenyl substituted from 1 to 5 times with fluorine orchlorine, and phenyl substituted from 1 to 3 times with a substituentselected from the group consisting of alkyl of from 1 to 6 carbon atoms,alkoxy of from 1 to 4 carbon atoms and phenyl. Most preferably, “aryl”refers to phenyl, tolyl, α-chlorotolyl, α-bromotolyl and methoxyphenyl.

In the context of the present invention, “heterocyclyl” refers topyridyl, furyl, pyrrolyl, thienyl, imidazolyl, pyrazolyl, pyrazinyl,pyrimidinyl, pyridazinyl, pyranyl, indolyl, isoindolyl, indazolyl,benzofuryl, isobenzofuryl, benzothienyl, isobenzothienyl, chromenyl,xanthenyl, purinyl, pteridinyl, quinolyl, isoquinolyl, phthalazinyl,quinazolinyl, quinoxalinyl, naphthyridinyl, phenoxathiinyl, carbazolyl,cinnolinyl, phenanthridinyl, acridinyl, 1,10-phenanthrolinyl,phenazinyl, phenoxazinyl, phenothiazinyl, oxazolyl, thiazolyl,isoxazolyl, isothiazplyl, and hydrogenated forms thereof known to thosein the art. Preferred heterocyclyl groups include pyridyl, furyl,pyrrolyl, thienyl, imidazolyl, pyrazolyl, pyrazinyl, pyrimidihyl,pyridazinyl, pyranyl and indolyl, the most preferred heterocyclyl groupbeing pyridyl. Accordingly, suitable vinyl heterocycles to be used as amonomer in the present invention include 2-vinyl pyridine, 4-vinylpyridine, 2-vinyl pyrrole, 3-vinyl pyrrole, 2-vinyl oxazole, 4-vinyloxazole, 2-vinyl thiazole, 4-vinyl thiazole, 2-vinyl imidazole, 4-vinylimidazole, 3-vinyl pyrazole, 4-vinyl pyrazole, 3-vinyl pyridazine,4-vinyl pyridazine, 3-vinyl isoxazole, 4-vinyl isoxazole, 3-vinylisothiazole, 4-vinyl isothiazole, 2-vinyl pyrimidine, 4-vinylpyrimidine, 5-vinyl pyrimidine, and 2-vinyl pyrazine, the most preferredbeing 2-vinyl pyridine. The vinyl heterocycles mentioned above may bearone or more substituents as defined above for an “aryl” group(preferably 1 or 2) in which each H atom may be independently replaced,e.g., with C₁-C₆ alkyl groups, C₁-C₆ alkoxy groups, cyano groups, estergroups or halogen atoms, either on the vinyl group or the heterocyclylgroup, but preferably on the heterocyclyl group. Further, those vinylheterocycles which, when unsubstituted, contain a N atom may bequaternized with an R⁸ (as defined above), and those which contain anN—H group may be protected at that position with a conventional blockingor protecting group, such as a C₁-C₆ alkyl group, a tris-(C₁-C₆alkyl)silyl group, an acyl group of the formula R¹⁰CO (where R¹⁰ isalkyl of from 1 to 20 carbon atoms in which each of the hydrogen atomsmay be independently replaced by halide [preferably fluoride orchloride]), alkenyl of from 2 to 20 carbon atoms (preferably vinyl),alkynyl of from 2 to 10 carbon atoms (preferably acetylenyl), phenyl,which may be substituted with from 1 to 5 halogen atoms or alkyl groupsof from 1 to 4 carbon atoms, or aralkyl (aryl-substituted alkyl, inwhich the aryl group is phenyl or substituted phenyl and the alkyl groupis from 1 to 6 carbon atoms, such as benzyl), etc. This definition of“heterocyclyl” also applies to the heterocyclyl groups in“heterocyclyloxy” and “heterocyclic ring.”

More specifically, preferred monomers include C₃-C₁₂ α-olefins,isobutene, (meth)acrylic acid and alkali metal salts thereof,(meth)acrylate esters of C₁-C₂₀ alcohols, acrylonitrile, acrylamide,cyanoacrylate esters of C₁-C₂₀ alcohols, didehydrbmalonate diesters ofC₁-C₆ alcohols, vinyl pyridines, vinyl N-C₁-C₆-alkylpyrroles, N-vinylpyrrolidones, vinyl oxazoles, vinyl thiazoles, vinyl pyrimidines, vinylimidazoles, vinyl ketones in which the α-carbon atom of the alkyl groupdoes not bear a hydrogen atom (e.g., vinyl C₁-C₆-alkyl ketones in whichboth α-hydrogens are replaced with C₁-C₄ alkyl, halogen, etc., or avinyl phenyl ketone in which the phenyl may be substituted with from 1to 5 C₁-C₆-alkyl groups and/or halogen atoms), and styrenes which maybear a C₁-C₆-alkyl group on the vinyl moiety (preferably at the α-carbonatom) and from 1 to 5 (preferably from 1 to 3) substituents on thephenyl ring selected from the group consisting of C₁-C₆-alkyl,C₁-C₆-alkenyl (preferably vinyl), C₁-C₆-alkynyl (preferably acetylenyl),C₁-C₆-alkoxy, halogen, nitro, carboxy, C₁-C₆-alkoxycarbonyl, hydroxyprotected with a C₁-C₆ acyl, SO₂R⁵, cyano and phenyl. The most preferredmonomers are isobutene, N-vinyl pyrrolidone, methyl acrylate (MA),methyl methacrylate (MMA), butyl acrylate (BA), 2-ethylhexyl acrylate(EHA), acrylonitrile (AN), styrene (St) and p-tert-butylstyrene.

In the present invention, the initiator may be any compound having oneor more atom(s) or group(s) which are radically transferable under thepolymerizing conditions. Suitable initiators include those of theformula:

R¹¹R¹²R¹³C—X

R¹¹C(═O)—X

R¹¹R¹²R¹³Si—X

R¹¹R¹²N—X

R¹¹N—X₂

 (R¹¹)_(n)P(O)_(m)—X_(3−n)

(R¹¹O)_(n)P(O)_(m)—X_(3−n) and

(R¹¹)(R¹²O)P(O)_(m)—X

where:

X is selected from the group consisting of Cl, Br, I, OR¹⁰ (as definedabove), SR¹⁴, SeR¹⁴, OC(═O)R¹⁴, OP(═O)R¹⁴, OP(═O) (OR¹⁴)₂, OP(═O)OR¹⁴,O—N(R¹⁴)₂, S—C(═S)N(R¹⁴)₂, CN, NC, SCN, CNS, OCN, CNO and N₃, where R¹⁴is aryl or a straight or branched C₁-C₂₀ (preferably C₁-C₁₀) alkylgroup, or where an N(R¹⁴)₂ group is present, the two R¹⁴ groups may bejoined to form a 5-, 6- or 7-membered heterocyclic ring (in accordancewith the definition of “heterocyclyl” above); and

R¹¹, R¹² and R¹³ are each independently selected from the groupconsisting of H, halogen, C₁-C₂₀ alkyl (preferably C₁-C₁₀ alkyl and morepreferably C₁-C₆ alkyl), C₃-C₈ cycloalkyl, R⁸ ₃Si, C(═Y)R⁵, C(═Y)NR⁶R⁷(where R⁵-R⁷ are as defined above), COCl, OH (preferably only one ofR¹¹, R¹² and R¹³ is OH), CN, C₂-C₂₀ alkenyl or alkynyl (preferably C₂-C₆alkenyl or alkynyl, and more preferably allyl or vinyl), oxiranyl,glycidyl, C₂-C₆ alkylene or alkenylene substituted with oxiranyl orglycidyl, aryl, heterocyclyl, aralkyl, aralkenyl (aryl-substitutedalkenyl, where aryl is as defined above, and alkenyl is vinyl which maybe substituted with one or two C₁-C₆ alkyl groups and/or halogen atoms[preferably chlorine]), C₁-C₆ alkyl in which from 1 to all of thehydrogen atoms (preferably 1) are replaced with halogen (preferablyfluorine or chlorine where 1 or more hydrogen atoms: are replaced, andpreferably fluorine, chlorine or bromine where 1 hydrogen atom isreplaced) and C₁-C₆ alkyl substituted with from 1 to 3 substituents(preferably 1) selected from the group consisting of C₁-C₄ alkoxy, aryl,heterocyclyl, C(═Y)R⁵ (where R⁵ is as defined above), C(═Y)NR⁶R⁷ (whereR⁶ and R⁷ are as defined above), oxiranyl and glycidyl; preferably suchthat no more than two of R¹¹, R¹² and R¹³ are H (more preferably no morethan one of R¹¹, R¹² and R¹³ is H);

m is 0 or 1; and

n is 0, 1 or 2.

In the present invention, X is preferably Cl or Br. Cl-containinginitiators generally provide (1) a slower reaction rate and (2) higherproduct polydispersity than the corresponding Br-containing initiators.However, Cl-terminated polymers generally have higher thermal stabilitythan the corresponding Br-terminated polymers.

When an alkyl, cycloalkyl, or alkyl-substituted aryl group is selectedfor one of R¹¹, R¹² and R¹³, the alkyl group may be further substitutedwith an X group as defined above. Thus, it is possible for the initiatorto serve as a starting molecule for branch or star (co)polymers. Oneexample of such an initiator is a 2,2-bis(halomethyl)-1,3-dihalopropane(e.g., 2,2-bis(chloromethyl)-1,3-dichloropropane,2,2-bis(bromomethyl)-1,3-dibromopropane), and a preferred example iswhere one of R¹¹, R¹² and R¹³ is phenyl substituted with from one tofive C₁-C₆ alkyl substituents, each of which may independently befurther substituted with a X group (e.g., α,α′-dibromoxylene, tetrakis-or hexakis(α-chloro- or α-bromomethyl)-benzene).

Preferred initiators include 1-phenylethyl chloride and 1-phenylethylbromide,(e.g., where R¹¹=Ph, R¹²=CH₃, R¹³=H and X=Cl or Br), chloroform,carbon tetrachloride, 2-chloropropionitrile, C₁-C₆-alkyl esters of a2-halo-C₁-C₆-carboxylic acid (such as 2-chloropropionic acid,2-bromopropionic acid, 2-chloroisobutyric acid, 2-bromoisobutyric acid,etc.), p-halomethylstyrenes and compounds of the formulaC₆H_(x)(CH₂X)_(y) or CX_(x′)[(CH₂)_(n)(CH₂X)]_(y′), where X is Cl or Br,x+y=6, x′+y′=4, 0≦n≦5 and both y′ and y≧1. More preferred initiatorsinclude 1-phenylethyl chloride, 1-phenylethyl bromide, methyl2-chloropropionate, ethyl 2-chloropropionate, methyl 2-bromopropionate,ethyl 2-bromoisobutyrate, p-chloromethylstyrene, α,α′-dichloroxylene,α,α′-dibromoxylene and hexakis(α-bromomethyl)benzene.

Any transition metal compound which can participate in a redox cyclewith the initiator and dormant polymer chain is suitable for use in thepresent invention. Preferred transition metal compounds are those whichdo not form a direct carbon-metal bond with the polymer chain.Particularly suitable transition metal compounds are those of theformula M_(t) ^(n+)X′_(n), where:

M_(t) ^(n+) may be, for example, selected from the group consisting ofCu¹⁺, Cu²⁺, Au⁺, Au²⁺, Au³⁺, Ag⁺, Ag²⁺, Hg⁺, Hg²⁺, Ni⁰, Ni⁺, Ni²⁺, Ni³⁺,Pd⁰, Pd⁺, Pd²⁺, Pt⁰, Pt⁺, Pt⁺², Pt⁺³, Pt⁺⁴, Rh⁺, Rh²⁺, Rh³⁺, Rh₄₊, Co⁺,Co²⁺, Co³⁺, Ir⁰, Ir⁺, Ir²⁺, Ir³⁺, Ir⁴⁺, Fe²⁺, Fe³⁺, Ru²⁺, Ru³⁺, Ru⁴⁺,Ru⁵⁺, Ru⁶⁺, Os²⁺, Os³⁺, Os⁴⁺, Re²⁺, Re³⁺, Re⁴⁺, Re⁶⁺, Re⁷⁺, Mn²⁺, Mn³⁺,Mn⁴⁺, Cr²⁺, Cr³⁺, Mo⁰, Mo⁺, Mo²⁺, Mo³⁺, W²⁺, W³⁺, V²⁺, V³⁺, V⁴⁺, V⁵⁺,Nb²⁺, Nb⁺³, Nb⁴⁺, Nb⁵⁺, Ta³⁺, Ta⁴⁺, Ta⁵⁺, Zn⁺ and Zn²⁺;

X′ may be, for example, selected from the group consisting of halogen,OH, (O)_(½), C₁-C₆-alkoxy, (SO₄)_(½), (PO₄)_(⅓), (HPO₄)_(½), (H₂PO₄),triflate, hexafluorophosphate, methanesulfonate, arylsulfonate(preferably benzenesulfonate or toluenesulfonate), SeR¹⁴, CN, NC, SCN,CNS, OCN, CNO, N₃ and R¹⁵CO₂, where R¹⁴ is as defined above and R¹⁵ is Hor a straight or branched C₁-C₆ alkyl group (preferably methyl) or aryl(preferably phenyl) which may be substituted from 1 to 5 times with ahalogen (preferably 1 to 3 times with fluorine or chlorine); and

n is the formal charge on the metal (e.g., 0≦n≦7).

Suitable ligands for use in the present invention include compoundshaving one or more nitrogen, oxygen, phosphorus and/or sulfur atomswhich can coordinate to the transition metal through a σ-bond, ligandscontaining two or more carbon. atoms which can coordinate to thetransition metal through a π-bond, ligands having a carbon atom whichcan coordinate to the transition metal through a σ-bond but which do notform a carbon-carbon bond with the monomer under the conditions of thepolymerizing step (e.g., ligands which do not participate in β-additionreactions with (coordinated) monomers; see, e.g., the ligand(s)described by van de Kuil et al, supra; and van Koten et al, Recl. Trav.Chim. Pays-Bas, 113, 267-277 (1994)), and ligands which can coordinateto the transition metal through a μ-bond or a η-bond.

Preferred N—, O—, P—and S— containing ligands may have one of thefollowing formulas:

R¹⁶—Z—R¹⁷ or

R¹⁶—Z—(R₁₈—Z)_(m)—R¹⁷

where:

R¹⁶ and R¹⁷ are independently selected from the group consisting of H,C₁-C₂₀ alkyl, aryl, heterocyclyl, and C₁-C₆ alkyl substituted with C₁-C₆alkoxy, C₁-C₄ dialkylamino, C(═Y)R⁵, C(═Y)R⁶R⁷ and/or YC(═Y)R⁸, where Y,R⁵, R⁶, R⁷ and R⁸ are as defined above; or

R¹⁶ and R¹⁷ can be joined to form a saturated, unsaturated orheterocyclic ring as described above for the “heterocyclyl” group;

Z is O, S, NR¹⁹ or PR¹⁹, where R¹⁹ is selected from the same group asR¹⁶ and R¹⁷,

each R¹⁸ is independently a divalent group selected from the groupconsisting of C₂-C₄ alkylene (alkanediyl) and C₂-C₄ alkenylene where thecovalent bonds to each Z are at vicinal positions (e.g., in a1,2-arrangement) or at β-positions (e.g., in a 1,3-arrangement) andC₃-C₈ cycloalkanediyl, C₃-C₈ cycloalkenediyl, arenediyl andheterocyclylene where the covalent bonds to each Z are at vicinalpositions; and

m is from 1 to 6.

In addition to the above ligands, each of R¹⁶—Z and R¹⁷—Z can form aring with the R¹⁸ group to which the Z is bound to form a linked orfused heterocyclic ring system (such as is i described above for“heterocyclyl”). Alternatively, when R¹⁶ and/or R¹⁷ are heterocyclyl, Zcan be a covalent bond (which may be single or double), CH₂ or a 4- to7-membered ring fused to R¹⁶ and/or R¹⁷, in addition to the definitionsgiven above for Z. Exemplary ring systems for the present ligand includebipyridyl, bipyrrole, 1,10-phenanthroline, a cryptand, a crown ether,etc.

Where Z is PR¹⁹, R¹⁹ can also be C₁-C₂₀-alkoxy.

Also included as suitable ligands in the present invention are CO(carbon monoxide), porphyrins and porphycenes, the latter two of whichmay be substituted with from 1 to 6 (preferably from 1 to 4) halogenatoms, C₁-C₆ alkyl groups, C₁-C₆-alkoxy groups, C₁-C₆ alkoxycarbonyl,aryl groups, heterocyclyl groups, and C₁-C₆ alkyl groups furthersubstituted with from 1 to 3 halogens.

Further ligands suitable for use in the present invention includecompounds of the formula R²⁰R²¹C(C(═Y)R⁵)₂, where Y and R⁵ are asdefined above, and each of R²⁰ and R²¹ is independently selected fromthe group consisting of H, halogen, C₁-C₂₀ alkyl, aryl and heterocyclyl,and R²⁰ and R²¹ may be joined to form a C₃-C₈ cycloalkyl ring or ahydrogenated (i.e., reduced, non-aromatic or partially or fullysaturated) aromatic or heterocyclic ring (consistent with thedefinitions of “aryl” and “heterocyclyl” above), any of which (exceptfor H and halogen) may be further substituted with 1 to 5 and preferably1 to 3 C₁-C₆ alkyl groups, C₁-C₆ alkoxy groups, halogen atoms and/oraryl groups. Preferably, one of R²⁰ and R²¹ is H or a negative charge.

Additional suitable ligands include, for example, ethylenediamine andpropylenediamine, both of which may be substituted from one to fourtimes on the amino nitrogen atom with a C₁-C₄ alkyl group or acarboxymethyl group; aminoethanol and aminopropanol, both of which maybe substituted from one to three times on the oxygen and/or nitrogenatom with a C₁-C₄ alkyl group; ethylene glycol and propylene glycol,both of which may be substituted one or two times on the oxygen atomswith a C₁-C₄ alkyl group; diglyme, triglyme, tetraglyme, etc.

Suitable carbon-based ligands include arenes (as described above for,the “aryl” group) and the cyclopentadienyl ligand. Preferredcarbon-based ligands include benzene (which may be substituted with fromone to six C₁-C₄ alkyl groups [e.g., methyl]) and cyclopentadienyl(which may be substituted with from one to five methyl groups, or whichmay be linked through an ethylene or propylene chain to a secondcyclopentadienyl ligand). Where the cyclopentadienyl ligand is used, itmay not be necessary to include a counteranion (X′) in the transitionmetal compound.

Preferred ligands include unsubstituted and substituted pyridines andbipyridines (where the substituted pyridines and bipyridines are asdescribed above for “heterocyclyl”), acetonitrile, (R¹⁰O)₃P, PR¹⁰ ₃,1,10-phenanthroline, porphyrin, cryptands such as K₂₂₂ and crown etherssuch as 18-crown-6. The most preferred ligands are bipyridyl,4,4′-dialkylbipyridyls and (R₁₀O)₃P.

A preformed transition metal-ligand complex can be used in place of amixture of transition metal compound and ligand without affecting thebehavior of the polymerization.

The present invention also concerns an improved atom or group transferradical polymerization process employing a solubilized catalyst, whichin a preferred embodiment, results in a homogeneous polymerizationsystem. In this embodiment, the method employs a ligand havingsubstituents rendering the transition metal-ligand complex at leastpartially soluble, preferably more soluble than the correspondingcomplex in which the ligand does not contain the substituents, and morepreferably, at least 90 to 99% soluble in the reaction medium.

In this embodiment, the ligand may have one of the formulas R¹⁶—Z—R₁₇,R¹⁶—Z—(R¹⁸—Z)_(m)—R¹⁷ or R²⁰R²¹C(C(═Y)R⁵)₂ above, where at least one ofR¹⁶ and R₁₇ or at least one of R²⁰ and R²¹ are C₂-C₂₀ alkyl, C₁-C₆ alkylsubstituted with C₁-C₆ alkoxy and/or C₁-C₄ dialkylamino, or are aryl orheterocyclyl substituted with at least one aliphatic substituentselected from the group consisting of C₁-C₂₀ alkyl, C₂-C₂₀ alkylene,C₂-C₂₀ alkynylene and aryl such that at least two, preferably at leastfour, more preferably at least six, and most preferably at least eightcarbon atoms are members of the aliphatic substituent(s). Particularlypreferred ligands for this embodiment of the invention include2,2′-bipyridyl having at least two alkyl substituents containing a totalof at least eight carbon atoms, such as 4,4′-di-(5-nonyl)-2,2′-bipyridyl(dNbipy), 4,4′-di-n-heptyl-2,2′-bipyridyl (dHbipy) and4,4′-di-tert-butyl-2,2′-bipyridyl (dTbipy).

Particularly when combined with the aforementioned process forpolymerizing a monomer in the presence of a small amount of transitionmetal redox conjugate, a substantial improvement in productpolydispersity is observed. Whereas heterogeneous ATRP yields polymerswith polydispersities generally ranging from 1.1 to 1.5, so-called“homogeneous ATRP” (e.g., based on dNbipy, dHbipy or dTbipy) withtransition metal redox conjugate present (e.g., Cu(I)/Cu(II)) yieldspolymers with polydispersities ranging from less than 1.05 to 1.10.

In the present polymerization, the amounts and relative proportions ofinitiator, transition metal compound and ligand are those effective toconduct ATRP. Initiator efficiencies with the presentinitiator/transition metal compound/ligand system are generally verygood (e.g., at least 25%, preferably at least 50%, more preferably ≦80%,and most preferably ≦90%). Accordingly, the amount of initiator can beselected such that the initiator concentration is from 10⁻⁴ M to 3 M,preferably 10⁻³-10⁻¹ M. Alternatively, the initiator can be present in amolar ratio of from 10⁻⁴:1 to 0.5:1, preferably from 10⁻³: 1 to5×10^(−2: 1), relative to monomer. An initiator concentration of 0.1-1 Mis particularly useful for preparing end-functional polymers.

The molar proportion of transition metal compound relative to initiatoris generally that which is effective to polymerize the selectedmonomer(s), but may be from 0.0001:1 to 10:1, preferably from 0.1:1 to5:1, more preferably from 0.3:1 to 2:1, and most preferably from 0.9:1to 1.1:1. Conducting the polymerization in a homogeneous system maypermit reducing the concentration of transition metal and ligand suchthat the molar proportion of transition metal compound to initiator isas low as 0.001:1.

Similarly, the molar proportion of ligand relative to transition metalcompound is generally that which is effective to polymerize the selectedmonomer(s), but can depend upon the number of coordination sites on thetransition metal compound which the selected ligand will occupy. (One ofordinary skill understands the number of coordination sites on a giventransition metal compound which a selected ligand will occupy.) Theamount of ligand may be selected such that the ratio of (a) coordinationsites on the transition metal compound to (b) coordination sites whichthe ligand will occupy is from 0.1:1 to 100:1, preferably from 0.2:1 to10:1, more preferably from 0.5:1 to 3:1, and most preferably from 0.8:1to 2:1. However, as is also known in the art, it is possible for asolvent or for a monomer to act as a ligand. For the purposes of thisapplication, however, the monomer is preferably (a) distinct from and(b) not included within the scope of the ligand, although in someembodiments (e.g., the present process for preparing a graft and/orhyperbranched (co)polymer), the monomer may be self-initiating (i.e.,Bicapable of serving as both initiator and monomer). Nonetheless,certain monomers, such as acrylonitrile, certain (meth)acrylates andstyrene, are capable of serving as ligands in the present invention,independent of or in addition to their use as a monomer.

The present polymerization may be conducted in the absence of solvent(“bulk” polymerization). However, when a solvent is used, suitablesolvents include ethers, cyclic ethers, C₅-C₁₀ alkanes, C₅-C₈cycloalkanes which may be substituted with from 1 to 3 C₁-C₄ alkylgroups, aromatic hydrocarbon solvents, halogenated hydrocarbon solvents,acetonitrile, dimethylformamide, ethylene carbonate, propylenecarbonate, dimethylsulfoxide, dimethylsulfone, water, mixtures of suchsolvents, and supercritical solvents (such as CO₂, C₁-C₄ alkanes inwhich any H may be replaced with F, etc.). The present polymerizationmay also be conducted in accordance with known suspension, emulsion,miniemulsion, gas phase, dispersion, precipitation and reactiveinjection molding polymerization processes, particularly miniemulsionand dispersion polymerization processes.

Suitable ethers include compounds of the formula R²²OR²³, in which eachof R²² and R²³ is independently an alkyl group of from 1 to 6 carbonatoms or an aryl group (such as phenyl) which may be further substitutedwith a C₁-C₄-alkyl or C₁-C₄-alkoxy group. Preferably, when one of R²²and R²³ is methyl, the other of R²² and R²³ is alkyl of from 4 to 6carbon atoms, C₁-C₄-alkoxyethyl or p-methoxyphenyl. Examples includediethyl ether, ethyl propyl ether, dipropyl ether, methyl t-butyl ether,di-t-butyl ether, glyme (dimethoxyethane), diglyme (diethylene glycoldimethyl ether), 1,4-dimethoxybenzene, etc.

Suitable cyclic ethers include THF and dioxane. Suitable aromatichydrocarbon solvents include benzene, toluene, o-xylene, m-xylene,pxylene and mixtures thereof. Suitable halogenated hydrocarbon solventsinclude CH₂Cl₂, 1,2-dichloroethane and benzene substituted from 1 to 6times with fluorine and/or chlorine, although preferably, the selectedhalogenated hydrocarbon solvent(s) does not act as an initiator underthe polymerization reaction conditions.

ATRP may also be conducted either in bulk or in an aqueous medium toprepare water-soluble or water-miscible polymers. Water-soluble polymersare important scientifically and commercially, because they find a widerange of applications in mineral-processing, water-treatment, oilrecovery, etc. (Bekturov, E. A.; Bakauova, Z. K. Synthetic Water-SolublePolymers in Solution, Huethig and Wepf: Basel, 1986; Molyneux, P.Water-Soluble Synthetic Polymers: Properties and Behavior, CRC Press:Boca Raton, Fla., 1991). Many of the industrially importantwater-soluble polymers are prepared by the free-radical polymerizationof acrylic and vinyl monomers, because this polymerization technique isamenable for use in aqueous solutions (Elias, H.; Vohwinkel, F. NewCommercial Polymers 2; Gordon and Breach: New York, 1986). For thesereasons, it is beneficial to develop well-controlled radicalpolymerizations for use in aqueous polymerizations (Keoshkerian, B.;Georges, M. K.; Boils-Boissier, D. Macromolecules 1995, 28, 6381).

Thus, the present ATRP process can be conducted in an aqueous medium. An“aqueous medium” refers to a water-containing mixture which is liquid atreaction and processing temperatures. Examples include water, eitheralone or admixed with a water-soluble C₁-C₄ alcohol, ethylene glycol,glycerol, acetone, methyl ethyl ketone, dimethylformamide,dimethylsulfoxide, dimethylsulfone, hexamethylphosphoric triamide, or amixture thereof. Additionally, the pH of the aqueous medium may beadjusted to a desired value with a suitable mineral acid or base (e.g.,phosphoric acid, hydrochloric acid, ammonium hydroxide, NaOH, NaHCO₃,Na₂CO₃, etc.). However, the preferred aqueous medium is water.

When conducted in an aqueous medium, the polymerization temperature maybe from 0° C. to the reflux temperature of the medium, preferably from20° C. to 100° C. and more preferably from 70° C. to 100° C. Preferably,the monomer(s) polymerized in this embodiment are at least partiallywater-soluble or water-miscible, or alternatively, capable of beingpolymerized in an aqueous emulsion which further comprises a surfactant(preferably in an amount sufficient to emulsify the monomer(s). Suchmonomers are preferably sufficiently soluble in 80° C. water to providea monomer concentration of at least 10⁻² M, and more preferably 10⁻¹ M.

Suitable water-soluble or water-miscible monomers include those of theformula:

wherein R¹ and R² are independently selected from the group consistingof H, halogen, CN, straight or branched alkyl of from 1 to 10 carbonatoms (preferably from 1 to 6 carbon atoms, more preferably from 1 to 4carbon atoms) which may be substituted, α,β-uxnsaturated straight orbranched alkenyl or alkynyl of 2 to 10 carbon atoms (preferably from 2to 6 carbon atoms, more preferably from 2 to 4 carbon atoms) which maybe substituted, C₃-C₈ cycloalkyl which may be substituted, NR⁸ ₂, N⁺R⁸₃, C(═Y)R⁵, C(═Y)NR⁶R⁷, YC(═Y)R⁸, YC(═Y)YR⁸, YS(═Y)R⁸, YS(═Y)₂R⁸,YS(═Y)₂YR⁸, P(R⁸)₂, P(═Y) (R⁸)₂, P(YR⁸)₂, P(═Y) (YR⁸)₂, P(YR⁸)R⁸, P(═Y)(YR⁸)R⁸, and aryl or heterocyclyl (as defined above) in which one ormore nitrogen atoms (if present) may be quaternized with an R⁸ group(preferably H or C₁-C₄ alkyl); where Y may be NR⁸, S or O (preferablyO), R⁵ is alkyl of from 1 to 10 carbon atoms, alkoxy of from 1 to 10carbon atoms, aryl, aryloxy or heterocyclyloxy; R⁶ and R⁷ areindependently H or alkyl of from 1 to 20 carbon atoms, or R⁶ and R⁷ maybe joined together to form an alkylene group of from 2 to 5 carbonatoms, thus forming a 3- to 6-membered ring; and R⁸ is (independently)H, straight or branched C₁-C₁₀ alkyl (which may be joined to form a 3-to 8-membered ring where more than one R⁸ group is covalently bound tothe same atom) or aryl, and when R⁸ is directly bonded to S or O, it maybe an alkali metal or an ammonium (N⁺R⁸ ₄) group; and

R³ and R⁴ are independently selected from the group consisting of H,halogen (preferably fluorine or chlorine), CN, C₁-C₆ (preferably C₁)alkyl and COOR⁹ (where R⁹ is as defined above); or

R¹ and R³ may be joined to form a group of the formula (CH₂)_(n′),(which may be substituted) or C(═O)—Y—C(═O), where n′ is from 2 to 6(preferably 3 or 4) and Y is as defined above;

at least two of R¹, R², R³ and R⁴ are H or halogen; and at least one ofR¹, R², R³ and R⁴ in at least one monomer is, or is substituted with,OH, NR⁸ ₂, N⁺R⁸ ₃, COOR⁹, C(═Y)R⁵, C(═Y)NR⁶R⁷, YC(═Y)R⁸, YC(═Y)YR⁸,YS(═Y)R⁸, YS(═Y)₂R₈, YS(═Y)₂YR⁸, P(YR⁸)₂, P(═Y) (YR⁸)₂, P(YR⁸)R⁸, P(═Y)(YR⁸)R⁸, P(═Y)R⁸ ₂, hydroxy-substituted C₁-C₁₀ alkyl or hetercyclyl inwhich one or more nitrogen atoms is quaternized with an R⁸ group (e.g.,H or C₁-C₄ alkyl).

A group “which m:ay be substituted” refers to the alkyl, alkenyl,alkynyl, aryl, heterocyclyl, alkylene and cycloalkyl groups substitutedin accordance with the descriptions herein. A preferred monomer is asulfonated acrylamide.

The present invention also encompasses water swellable polymers andhydrogels. Hydrogels are polymers which, in the presence of water, donot dissolve, but absorb water and thus swell in size. These polymershave found wide applications ranging from drug delivery to oil recovery.Generally, these polymeric materials are synthesized by radicalpolymerization of a water-soluble material in the presence of a divinylmonomer. The divinyl monomer introduces chemical cross links which makesthe polymer permanently insoluble in any solvent (i.e., withoutdegrading the polymer and its physical properties).

The present ATRP process also provides a process for synthesizing ahydrogel which utilizes physical cross links between chains and whichallows for dissolution of the polymer without loss of physicalproperties. The present water swellable polymers and hydrogel polymerscan also be processed from a melt, a characteristic that polymers havingchemical crosslinks lack. The water-soluble monomers described above maybe used to prepare the present water swellable (co)polymers andhydrogels. An exemplary polymer which was synthesized to demonstratesuch abilities is poly(N-vinylpyrrolidinone-g-styrene) (see the Examplesbelow).

In a preferred embodiment, the hydrogel comprises a base (co)polymer andat least two (preferably at least three, more preferably at least four,and even more preferably at least five) relatively hydrophobicside-chains grafted thereonto (e.g., by conventional radicalpolymerization or by the present ATRP process). The base (co)polymer maybe a (co)polymer containing a water-soluble or water-miscible monomer inan amount,sufficient to render the (co)polymer water-soluble orwater-miscible (e.g., containing at least 10 mol. %, preferably at:least30 mol. %, and preferably at least 50 mol. % of the water-soluble orwater-miscible monomer). Preferred hydrophobic side-chains containmonomeric units of the formula —R¹R²C—CR³R⁴—, in which:

R¹ and R² are independently selected from the group consisting of H,halogen, CN, straight or branched alkyl of from 1 to 10 carbon atoms(preferably from 1 to 6 carbon atoms, more preferably from 1 to 4 carbonatoms) which may be substituted, straight or branched alkenyl or alkynylof from 2 to 10 carbon atoms (preferably from 2 to 6 carbon atoms, morepreferably from 2 to 3 carbon atoms) which may be substituted, C₃-C₈cycloalkyl which may be substituted, NR⁸ ₂, C(═Y)R⁵, C(═Y)NR⁶R⁷,YC(═Y)R⁸, YC(═Y)YR⁸, YS(═Y)R⁸, YS(═Y)₂R⁸, YS(═Y)₂YR⁸, P(R⁸)₂, P(═Y)(R⁸)₂, P(YR⁸)₂, P(═Y) (YR⁸)₂, P(YR⁸)R⁸, P(═Y) (YR⁸)R⁸, and aryl orheterocyclyl in which each H atom may be replaced with halogen atoms,NR⁸ ₂, C₁-C₆alkyl or C₁-C₆ alkoxy groups; where Y may be NR⁸, S or O(preferably O); R⁵ is alkyl of from 1 to 10 carbon atoms, alkoxy of from1 to 10 carbon atoms, aryl, aryloxy or heterocyclyloxy; R⁶ and R⁷ arealkyl of from 1 to 20 carbon atoms, or R⁶ and R⁷ may be joined togetherto form an alkylene group of from 2 to 7 carbon atoms, thus forming a 3-to 8-membered ring; and R⁸ is (independently) straight or branchedC₁-C₁₀ alkyl (which may be joined to form a 3- to 7-membered ring wheremore than one R⁸ group is covalently bound to the same atom); and

R³ and R⁴ are independently selected from the group consisting of H,halogen (preferably fluorine or chlorine), CN, C₁-C₆ (preferably C₁)alkyl and COOR⁹ (where R⁹ is alkyl of from 1 to 10 carbon atoms oraryl);

R¹ and R³ may be joined to form a group of the formula (CH₂)_(n′) (whichmay be substituted) where n′ is from 2 to 6 (preferably 3 or 4); and

at least two of R¹, R², R³ and R⁴ are H or halogen.

Polymers produced by the present process may be useful in general asmolding materials (e.g., polystyrene containers) and as barrier orsurface materials (e.g., poly(methyl methacrylate), or PMMA, iswell-known in this regard as PLEXIGLAS™). However, the polymers producedby the present process, which typically will have uniform, predictable,controllable and/or tunable properties relative to polymers produced byconventional radical polymerization, will be most suitable for use inspecialized or performance applications.

For example, block copolymers of polystyrene and polyacrylate (e.g.,PSt-PA-PSt triblock copolymers) are useful thermoplastic elastomers.Poly(methyl methacrylate)-polyacrylate triblock copolymers (e.g.,PMMA-PA-PMMA) are useful, fully acrylic thermoplastic elastomers. Homo-and copolymers of styrene, (meth)acrylates and/or acrylonitrile areuseful plastics, elastomers and adhesives. Either block or randomcopolymers of styrene and a (meth)acrylate or acrylonitrile may beuseful thermoplastic elastomers having high solvent resistance.

Furthermore, block copolymers in which the blocks alternate betweenpolar monomers and non-polar monomers produced by the present inventionare useful amphiphilic surfactants or dispersants for making highlyuniform polymer blends. Star polymers produced by the present processare useful high-impact (co)polymers. (For example, STYROLUX™, ananionically-polymerized styrene-butadiene star block copolymer, is aknown, useful high-impact copolymer.)

The (co)polymeris of the present invention (and/or a block thereof) mayhave an average degree of polymerization (DP) of at least 3, preferablyat least 5, and more preferably at least 10, and may have a weightand/or number average molecular weight of at least 250 g/mol, preferablyat least 500 g/mol, more preferably at least 1,000 g/mol, even morepreferably at least 2,000 g/mol, and most preferably at least 3,000g/mol. The present (co)polymers, due to their “living” character, canhave a maximum molecular weight without limit. However, from a practicalperspective, the present (co)polymers and blocks thereof may have anupper weight or number average molecular weight of, e.g., 5,000,000g/mol, preferably 1,000,000 g/mol, more preferably 500,000 g/mol, andeven more preferably 250,000 g/mol. For example, when produced in bulk,the number average molecular weight may be up to 1,000,000 (with aminimum weight or number average molecular weight as mentioned above).

The number average molecular weight may be determined by size exclusionchromatography (SEC) or, when the initiator has a group which can beeasily distinguished from the monomer(s), by NMR spectroscopy (e.g.,when 1-phenylethyl chloride is the initiator and methyl acrylate is themonomer).

Thus, the present invention also encompasses novel end-functional,telechelic and-hyperbranched homopolymers, and block, multi-block, star,gradient, random, graft or “comb” and hyperbranched copolymers. Each ofthe these different types of copolymers will be described hereunder.

Because ATRP is a “living” polymerization, it can be started andstopped, practically at will. Further, the polymer product retains thefunctional group “X” necessary to initiate a further polymerization.Thus, in one embodiment, once the first monomer is consumed in theinitial polymerizing step, a second monomer can then be added to form asecond block on the growing polymer chain in a second polymerizing step.Additional polymerizations with the same or different monomer(s) can beperformed to prepare multi-block copolymers.

Furthermore, since ATRP is radical polymerization, blocks can beprepared in essentially any order. One is not necessarily limited.topreparing block copolymers where the sequential polymerizing steps mustflow from the least stabilized polymer intermediate to the moststabilized polymer intermediate, such as is necessary in ionicpolymerization. Thus, one can prepare a multi-block copolymer in which apolyacrylonitrile or a poly(meth)acrylate block is prepared first, thena styrene or butadiene block is attached thereto, etc.

As is described throughout the application, certain advantageousreaction design choices will become apparent. However, one is notlimited to those advantageous reaction design choices in the presentinvention.

Furthermore, a linking group is not necessary to join the differentblocks of the present block copolymer. One can simply add successivemonomers to form successive blocks. Further, it is also possible (and insome cases advantageous) to first isolate a (co)polymer produced by thepresent ATRP process, then react the polymer with an additional monomerusing a different initiator/catalyst system (to “match” the reactivityof the growing polymer chain with the new monomer). In such a case, theproduct polymer acts as the new initiator for the further polymerizationof the additional monomer.

Thus, the present invention also encompasses end-functional homopolymershaving a formula:

A—[(M¹)_(h)]—X

and random copolymers having a formula:

A—[(M¹)_(i)(M²)_(j)]—X

A—[(M¹)_(i)(M²)_(j)(M³)_(k)]—X or

 A—[(M¹)_(i)(M²)_(j)(M³)_(k) . . . (M^(u))_(l)]—X

where A may be R¹¹R¹²R¹³C, R¹¹R¹²R¹³Si, (R¹¹)_(m)Si, R¹¹R¹²N,(R¹¹)_(n)P, (R¹¹O)_(n)P, (R¹¹) (R¹²O)P, (R¹¹)_(n)P(O), (R¹¹O)_(n)P(O) or(R¹¹) (R¹²O) P(O); R¹¹, R¹², R¹³ and X are as defined above; M₁, M₂, M₃,. . . up to M^(u) are each a radically polymerizable monomer (as definedabove); h, i, j, k . . . up to l are each average degrees ofpolymerization of at least 3; and i, j, k . . . up to l represent molarratios of the radically polymerizable monomers M¹, M², M³, . . . up toM^(u).

Preferably, at least one of M¹, M², M³, . . . up to M^(u) has theformula:

wherein at least one of R¹ and R² is CN, CF₃, straight or branched alkylof from 4 to 20 carbon atoms (preferably from 4 to 10 carbon atoms, morepreferably from 4 to 8 carbon atoms), C₃-C₈ cycloalkyl, aryl,heterocyclyl, C(═Y)R⁵, C(═Y)NR⁶R⁷ and YC (═Y)R⁸, where aryl,heterocyclyl, Y, R⁵, R⁶, R⁷ and R⁸ are as defined above; and

R³ and R⁴ are as defined above; or

R¹ and R³ are joined to form a group of the formula (CH₂)_(n′) orC(═O)—Y—C(═O), where n′ and Y are as defined above.

Preferably, these (co)polymers have either a weight or number averagemolecular weight of at least 250 g/mol, more preferably at least 500g/mol, even more preferably 1,000 g/mol and most preferably at least3,000 g/mol. Preferably, the (co)polymers have a polydispersity of 1.50or less, more preferably 1.35 or less, even more preferably 1.25 or lessand most preferably 1.20 or less. Although the present gels may have aweight or number average molecular weight well above 5,000,000 g/mol,from a practical perspective, the present (co)polymers and blocksthereof may have an upper weight or number average molecular weight of,e.g., 5,000,000 g/mol, preferably 1,000,000 g/mol, more preferably500,000 g/mol, and even more preferably 250,000 g/mol.

Preferred random copolymers include those prepared from any combinationof styrene, vinyl acetate, acrylonitrile, acrylamide and/or C₁-C₈ alkyl(meth)acrylates, and particularly include those of (a) methylmethacrylate and styrene having from 10 to 75 mol % styrene, (b) methylmethacrylate and methyl acrylate having from 1 to 75 mol % methylacrylate, (c) styrene and methyl acrylate, and (d) methyl methacrylateand butyl acrylate.

The present invention also concerns block copolymers of the formula:

A—(M¹)_(p)—(M²)_(q)—X

 A—(M¹)_(p)—(M²)_(q)—(M³)_(r)—X

A—(M¹)_(p)—(M²)_(q)—(M³)_(r)— . . . —(M^(u))_(s)—X

wherein A and X areas defined above; M¹, M², M³, . . . up to M^(u) areeach a radically polymerizable monomer (as defined above) selected suchthat the monomers in adjacent blocks are not identical (althoughmonomers in non-adjacent blocks may be identical) and p, q, r, . . . upto s are independently selected such that the average degree ofpolymerization and/or the weight or number average molecular weight ofeach block or of the copolymer as a whole may be as described above forthe present (co)polymers. After an appropriate end group conversionreaction (conducted in accordance with known methods), X may also be,for example, H, OH, N₃, NH₂, COOH or CONH₂.

Preferred block :copolymers may have the formula

R¹¹R¹²R¹³C—(M¹)_(p)—(M²)_(q)—X

R¹¹R¹²R¹³C—(M¹)_(p)—(M²)_(q)—(M³)_(r)—X or

R¹¹R¹²R¹³C—(M¹)_(p)—(M²)_(q)—(M³)_(r)— . . . —(M^(u))_(s)—X

Preferably, each block of the present block copolymers has apolydispersity of 1.50 or less, more preferably 1.35 or less, even morepreferably 1.25 or less and most preferably 1.20 or less. The presentblock copolymer, as a complete unit, may have a polydispersity of 3.0 orless, more preferably 2.5 or less, even more preferably 2.0 or less andmost preferably 1.50 or less.

The present invention may be used to prepare periodic or alternatingcopolymers. The present ATRP process is particularly useful forproducing alternating copolymers where one of the monomers has one ortwo bulky substituents (e.g., where at least one of M¹, M², M³, . . . upto M^(u) are each 1,1-diarylethylene, didehydromalonate C₁-C₂₀ diesters,C₁-C₂₀ diesters of maleic or fumaric acid, maleic anhydride and/ormaleic diimides [where Y is NR₈ as defined above], etc.), from whichhomopolymers may be difficult to prepare, due to steric considerations.Thus, some preferred monomer combinations for the present alternatingcopolymers containing “bulky” substituents include combinations ofstyrene, acrylonitrile and/or C₁-C₈ esters of (meth)acrylic acid, withmaleic anhydride, C₁-C₈ alkyl maleimides and/or 1,1-diphenylethylene.

Copolymerization of monomers with donor and acceptor properties resultsin the formation of products with predominantly alternating monomerstructure (Cowie, “Alternating Copolymerization,” Comprehensive PolymerScience, vol. 4, p. 377, Pergamon Press (1989)). These copolymers canexhibit interesting physical and mechanical properties that can beascribed to their alternating structure (Cowie, Alternating Copolymers,Plenum, New York (1985)).

So-called “alternating” copolymers can be produced using the presentmethod. “Alternating” copolymers are prepared by copolymerization of oneor more monomers having electron-donor properties (e.g., unsaturatedhydrocarbons, vinyl ethers, etc.) with one or more monomers havingelectron acceptor type properties (acrylates, methacrylates, unsaturatednitriles, unsaturated ketones, etc.). Thus, the present invention alsoconcerns an alternating copolymer of the formula:

A—(M¹—M²)_(p)—X

A—(M¹—M²)_(p)—(M²—M¹)_(q)—X

A—(M¹—M²)_(p)—(M²—M¹)_(q)—(M¹—M²)_(r)—X or

A—[(M¹—M²)_(p)—(M²—M¹)_(q)—(M¹—M²)_(r)— . . . —(M^(v)—M^(y))_(s)—X

where A and X are as defined above, M¹ and M² are differentradically-polymerizable monomers (as defined above), and M^(v) is one ofM¹ and M² and M^(y) is the other of M¹ and M². However, p, q, r, . . .up to s are independently selected such that the average degree ofpolymerization and/or the weight or number average molecular weight ofthe copolymer as a whole or of each block may be described above for thepresent end-functional or random (co)polymers. (The description “r . . .up to s” indicates that any number of blocks equivalent to thosedesignated by the subscripts p, q and r can exist between the blocksdesignated by the subscripts r and s.)

Preferably, A is R¹¹R¹²R¹³C, M¹ is one or more monomers havingelectron-donor properties (e.g., C₂-C₂₀ unsaturated hydrocarbons whichmay have one or more alkyl, alkenyl, alkynyl, alkoxy, alkylthio,dialkylamino, aryl or tri(alkyl and/or aryl)silyl substituents asdefined above [e.g., isobulene or vinyl C₂-C₁₀ ethers], etc.) and M² isone or more monomers having electron acceptor properties (e.g.,(meth)acrylic acid or a salt thereof, C₁-C₂₀ (meth)acrylate esters,C₃-C₂₀ unsaturated nitriles, C₃-C₂₀ α,β-unsaturated aldehydes, ketones,sulfones, phosphates, sulfonates, etc., as defined above).

Preferably, the present alternating copolymers have either a weight ornumber average molecular weight of at least 250 g/mol, more preferably500 g/mol, even more preferably 1,000 g/mol, and most preferably 3,000g/mol. Preferably, the present alternating copolymers have a maximumweight or number average molecular weight of 5,000,000 g/mol, preferably1,000,000 g/mol and even more preferably 500,000 g/mol, although theupper the limit of the molecular weight of the present “living” (co)polymers is not limited. Preferably, the present alternating copolymershave a polydispersity of 1.50 or less, more preferably 1.35 or less,even more preferably 1.25 or less and most preferably 1.20 or less.

The present random or alternating copolymer can also serve as a block inany of the present block, star, graft, comb or hyperbranched copolymers.

Where the A (or preferably R¹¹R¹²R¹³C) group of the initiator contains asecond “X” group, ATRP may be used to prepare “telechelic” (co)polymers.“Telechelic” homopolymers may have the following formula:

X—M_(p)—(A)—M_(p)—X

where A (preferably R¹¹R¹²R¹³C) and X are as defined above, M is aradically polymerizable monomer as defined above, and p is an averagedegree of polymerization of at least 3, subject to the condition that Ais a group bearing an X substituent.

Preferred telechelic homopolymers include those of styrene,acrylonitrile, C₁-C₈ esters of (meth)acrylic acid, vinyl chloride, vinylacetate and tetrafluoroethylene. Such telechelic homopolymers preferablyhave either a weight or number average molecular weight of at least 250g/mol, more preferably at least 500 g/mol, even more preferably at least1,000 g/mol, and most preferably at least 3,000 g/mol, and/or have apolydispersity of 1.50 or less, more preferably 1.3 or less, even morepreferably 1.2 or less and most preferably 1.15 or less. From apractical standpoint, the present alternating copolymers may have amaximum weight or number average molecular weight of 5,000,000 g/mol,preferably 1,000,000 g/mol, more preferably 500,000 g/mol, and even morepreferably 250,000 g/mol, although the upper limit of the molecularweight of the present “living” (co)polymers is not particularly limited.

Block copolymers prepared by ATRP from an initiator having a second “X”group may have one of the following formulas:

X—(M²)_(q)—(M¹)_(p)—(A)—(M¹)_(p)—(M²)_(q)—X

X—(M³)_(r)—(M²)_(q)—(M¹)_(p)—(A)—(M¹)_(p)—(M²)_(q)—(M³)_(r)—X

X—(M^(u))_(s)— . . .—(M³)_(r)—(M²)_(q)—(M¹)_(p)—A—(M¹)_(p)—(M²)_(q)—(M³)_(r)— . . .—(M^(u))_(s)—X

and random copolymers may have one of the following formulas:

X—[(M¹)_(p)(M²)_(q)]—(A)—[(M¹)_(p)(M²)_(q)]—X

X—[(M¹)_(p)(M²)_(q)(M³)_(r)]—(A)—[(M¹)_(p)(M²)_(q)(M³)_(r)]—X

X—[(M¹)_(p) . . .(M²)_(q)(M³)_(r)—(M^(u))_(s)]—A—[(M¹)_(p)(M²)_(q)(M³)_(r) . . .(M^(u))_(s)]—X

where A (preferably R¹¹R¹²R¹³C), X, M¹, M², M³, . . . up to M^(u), andp, q, r, . . . up to s are as defined above, subject to the conditionthat A is a group bearing an X substituent.

The present invention also concerns gradient copolymers. Gradientcopolymers form an entirely new class of polymers with a controlledstructure and composition which changes gradually and in a systematic anpredictable manner along the copolymer chain (FIG. 10). Due to thiscomposition distribution and consequent unusual interchain interactions,gradient copolymers are expected to have very unique thermal properties(e.g., glass transition temperatures and/or melting points). They mayalso exhibit unprecedented phase separation and uncommon mechanicalbehavior, and may provide unique abilities as surfactants or asmodifiers for blending incompatible materials.

Gradient copolymers can be obtained in a system without a significantchain-breaking reaction, such as ATRP. To control the copolymercomposition, it is beneficial to maintain continuous growth of thepolymer chain and regulate the comonomers' feed composition during thecourse of the reaction. Otherwise, the distribution of the monomer unitsalong the polymer chain may be random or block-like.

To date, there are no publications on the subject of gradientcopolymers. The closest examples described so far are tapered copolymersprepared through living anionic polymerization (Sardelis et al, Polymer,25, 1011 (1984) and Polymer, 28, 244 (1987); Tsukuhara et al, Polym. J.,12, 455 (1980)). Tapered copolymers differ from gradient copolymerssince they retain block-like character despite the composition gradientin the middle block. Additionally, the compositional gradient of taperedpolymers is inherent and cannot be changed or controlled.

Gradient copolymers may be prepared via ATRP 5 copolymerization of twoor more monomers with different homopolymerization reactivity ratios(e.g., r¹>>r₂, where r¹ may be greater than 1 and r₂ may be less than1). Such comonomers usually do not copolymerize randomly (Odian,Principles of Polymerization, 3rd ed., John Wiley & Sons, New York, p.463 (1991)). For example, in conventional radical polymerization, amixture of homopolymers is obtained.

In the present controlled system, where the polymer chain is notterminated at any stage of the reaction, initially only the more (ormost) reactive monomer reacts until its concentration decreases to sucha level that the less (or second most) reactive monomer begins toincorporate into the growing polymer chains. The less reactive monomeris gradually incorporated into the polymer chain to a greater extent,and its content in the chain increases, as the more reactive monomer isfurther consumed. Finally, only the least reactive monomer is present inthe system and as it reacts, it forms a block of the least reactivemonomer at the end of the chain. The gradient of composition in such acopolymer is controlled by the difference in the reactivity ratios andthe rate with which each of the monomers reacts. It might also beconsidered an inherent control over the copolymer's composition, whichcan be altered by intentionally changing the concentration of one ormore of the monomers.

Thus, in an example of the gradient copolymerization including twodistinct monomers, the polymerizing step of the present method ofcontrolled atom or group transfer polymerization may comprisepolymerizing first and second radically polymerizable monomers presentin amounts providing a molar ratio of the first monomer to the secondmonomer of from a:b to b:a, where a and b are each from 0 to 100 and(a+b)=100, then adding an additional amount of the first and/or secondmonomer providing a molar ratio of the first monomer to the secondmonomer of from c:d to d:c, where c differs from a, d differs from b and(c+d)=100, and if desired, repeating as often as desired the adding stepsuch that if c>a, the molar proportion (or percentage) of the firstmonomer increases, but if d>b, the molar proportion (or percentage) ofthe second monomer increases. The adding step(s) may be continuous, inintermittent portions or all at once.

Thus, the present invention also encompasses a gradient copolymer of theformula:

A—M¹ ^(n)—(M¹ _(a)M² _(b))_(x)— . . . —(M¹ ^(c)M² _(d))_(y)—M² _(m)—X

where A and X are as defined above, M¹ and M² areradically-polymerizable monomers (as defined above) having differentreactivities (preferably in which the ratio of homopolymerization and/orcopolymerization reactivity rates are at least 1.5, more preferably atleast 2 and most preferably at least 3), a, b, c and d are non-negativenumbers independently selected such that a+b=c+d=100, wherein the a:bratio is from 99:1 to 50:50, the c:d ratio is from 50:50 to 99:1, andthe molar proportion of M¹ to M² gradually decreases along the length ofthe polymer chain from a:b to c:d, and n, m, x and y are independentlyan integer of at least 2, preferably at least 3, more preferably atleast 5 and most preferably at least 10. The weight or number averagemolecular weight of each block or of the copolymer as a whole may be asdescribed above for the present (co)polymers. Preferably, A isR¹¹R¹²R¹³C, and X is a halogen.

To determine the gradient, the copolymerization can be intermittentlysampled, and the molar proportion of units of the copolymercorresponding to each monomer determined in accordance with knownmethods. As long as the proportion of one monomer increases as theother(s) decrease(s) during the course of the copolymerization, themolar proportion of the one monomer increases along the length of thepolymer chain as the other(s) decrease(s).

Alternatively, the decrease of the monomer ratio along the length of thepolymer chain a:b to c:d can be determined in accordance with thenumbers of monomer units along the polymer chain. The number ofsubblocks must be smaller than the number of monomeric units in eachsubblock, but the subblocks may overlap by a number of monomer unitssmaller than the size of the subblock. For example, where the centralblock of the polymer contains 6 monomeric units, the ratios may bedetermined for two 3-unit subblocks (e.g., (3-mer)-(3-mer)). Where thecentral block of the polymer contains, for example 9 monomeric units,the ratios may be determined for three 4-unit subblocks where thecentral subblock overlaps each terminal subblock by one monomer unit(e.g., (4-mer)-(overlapping 4-mer)-(4-mer). Where the central block ofthe polymer contains, for example, from 10 to 50 monomeric units, theratios may be determined for 5- to 10-unit subblocks (e.g.,(5-mer)-(5-mer), (6-mer)-(8-mer)-(6-mer), (10-mer)-(10-mer),(5-mer)-(5-mer)-(5-mer)-(5-mer), etc.). Where the central block of thepolymer contains, for example, from 51 to 380 monomeric units, theratios may be determined for 10- to 20-unit subblocks; etc. Suchcopolymers can be prepared by carefully controlling the molar ratios ofmonomers to each other and to initiator or dormant polymer chains.

In a further embodiment, the relative proportions of first monomer tosecond monomer are controlled in a continuous manner, using for exampleby adding the second monomer via a programmable syringe or feedstocksupply pump.

When either the initiator or monomer contains a substituent bearing aremote (i.e., unconjugated) ethylene or acetylene moiety, ATRP can beused to prepare cross-linked polymers and copolymers.

The present invention is also useful for forming so-called “star”polymers and copolymers. Thus, where the initiator has three or more “X”groups, each of the “X” groups can serve as a polymerization initiationsite. Thus, the present invention also encompasses star (co)polymers ofthe formula:

A′—[(M¹)_(p)—X]_(z)

A′—[(M¹)_(p)—(M²)_(q)—X]_(z)

A′—[(M¹)_(p)—(M²)_(q)—(M³)_(r)—X]_(z)

A′—[(M¹)_(p)—(M²)_(q)—(M³)_(r)— . . . —(M^(u))_(s)—X]_(z)

A′—[(M¹ ^(i)M² _(j))—X]_(z)

A′—[(M¹ _(i)M² _(j)M³ _(k))—X]_(z)

A′—[(M¹ _(i)M² _(j)M³ _(k) . . . M^(u) _(l))—X]_(z)

where A′ is the same as A with the proviso that R¹¹, R¹² and R¹³combined contain from 2 to 5 X groups, where X is as defined above; M¹,M², M³, . . . M^(u) are as defined above for the present blockcopolymers; and z is from 3 to 6. Preferably, A′ is R¹¹R¹²R¹³C, and X ishalogen (preferably chlorine or bromine).

Initiators suitable for use in preparing the present star (co)polymersare those in which the A (or preferably R¹¹R¹²R¹³C) group possesses atleast three substituents which can be “X” (as defined above).Preferably, these substituents are identical to “X”. Examples of suchinitiators include compounds of the formula C₆H_(x)(CH₂X)_(y) orCH_(x′)(CH₂X)_(y′), where X is a halogen, x+y=6, x′+y′=4 and y and y′are each ≧3. Preferred initiators of this type include2,2-bis(chloromethyl)-1,3-dichloropropane,2,2-bis(bromomethyl)-1,3-dibromopropane), α,α′,α″-trichloro- andα,α′,α″-tribromocumene, and tetrakis- and hexakis(α-chloro- andα-bromomethyl)benzene), the most preferred beinghexakis(α-bromomethyl)benzene.

Branched and hyperbranched polymers may also be prepared in accordancewith the present invention. The synthesis of hyperbranched polymers hasbeen explored to develop dendritic molecules in a single, one-potreaction.

Conventional hyperbranched polymers are obtained by the reaction of AB₂monomers in which A and B are moieties containing functional groupscapable of reacting with each other to form stable bonds. Because of theAB₂ structure of the monomers, reaction of two monomers results in theformation of a dimer with one A group and three B groups. This processrepeats itself by reaction with either monomer, dimer, trimer, etc., ina similar fashion to provide step-wise growth of polymers.

The resulting polymer chains have only one A group and (n+1) B groups,where n is the number of repeat units. Polymers resulting from thesereactions are sometimes highly functionalized. These polymers, however,do not have perfectly symmetrical architectures, but rather, are ofirregular shapes. This may be due to uneven growth of the macromoleculein various directions.

The present hyperbranched polymers have some of the qualities ofdendrimers, but may lack some properties of perfect dendrimers. Thecationic process described by Frechet et al. (Science 269, 1080 (1995))differs from the present synthesis of hyperbranched polymers not only inthe mechanism of polymerization, but also by extending the reaction toprimary benzyl halides.

The present invention also concerns a process for preparinghyperbranched polymers (e.g., hyperbranched v10 polystyrene) by atom orgroup transfer radical polymerization (ATRP), preferably in “one-pot”(e.g., in a single reaction sequence without substantial purificationsteps, and more specifically, in a single reaction vessel without anyintermediate purification steps), using the present process and at leastone radically polymerizable monomer in which at least one of R¹, R², R³and R⁴ also contains a radically transferable X group, optionally in theabsence of an initiator (or if an initiator is used, the X group of themonomer may be the same or different from the X group of the initiator).

For example, commercially available p-chloromethylstyrene (p-CMS) may bepolymerized in the presence of a transition metal compound (e.g., Cu(I))and ligand (e.g., 2,2′-bipyridyl, or “bipy”). A demonstrative example ofthe copolymerization of styrene and p-CMS, and its comparison with alinear standard, is presented in the Examples below.

In fact, the monomer may also act as initiator (e.g., thehomopolymerization of p-CMS in the presence of Cu(I) and bipy). It ispossible to remove the chlorine atom at the benzylic positionhomolytically, thus forming Cu(II)Cl₂ and a benzyl radical capable ofinitiating the polymerization of monomer through the double bonds (seeScheme 3). This results in the formation of a polymer chain with pendantgroups consisting of p-benzyl chloride. Also, the polymer has a doublebond at the chain end which can be incorporated into a growing polymerchain.

Thus, the present invention also concerns a hyperbranched (co)polymer ofthe formula:

where M¹ is a radically polymerizable monomer having both acarbon-carbon multiple bond and at least one X group (as defined above);M², M³ . . . up to M^(u) are radically polymerizable monomers (asdefined above); a, b, c . . . up to d are numbers of at least zero suchthat the sum of a, b, c . . . up to d is at least 2, preferably at least3, more preferably at least 4 and most preferably at least 5; e is thesum of the products of (i) a and the number of X groups on M¹, (ii) band the number of X groups on M², (iii) c and the number of X groups onM³ . . . up to (iv) d and the ;number of X groups on M^(u); f≦e and(g+h+i+j+k)=e.

The formula “M¹—(M¹ _(a)M² _(b)M³ _(c) . . . M^(u) _(d))—X_(e)”represents a “perfect” hyperbranched polymer, in which each “X” group isat the end of a chain or branch of monomeric units. (In the presenthyperbranched (co)polymer, a “chain” may be defined as the longestcontinuous series of monomeric units of a polymer. A “branch” may bedefined as any covalently-bound series of monomer units in the polymercontaining a number of monomeric units smaller than the “chain”.) Theformula:

represents those (co)polymers in which one or more “X” groups are boundto non-terminal monomer units (i.e., monomer units not at the end of abranch or chain).

In fact, the present invention also encompasses those (co)polymers inwhich the “X” substituent is located at either or both ends of the(co)polymer chain, on an internal monomeric unit, or any combinationthereof. “Internal” X groups can be put into place by incorporating intothe polymer chain a monomer having a substituent encompassed by thedefinition of “X” above.

In the present hyperbranched (co)polymer, the number of branches will beat most 2^((a−1))−1, assuming all “X” groups are active in subsequentATRP steps. Where, for example, a number “h” of “X” groups fail to reactin subsequent ATRP steps (e.g., where one of the 1° or 2° Cl groups on abranch in the octamer shown in Scheme 3 below does not react insubsequent ATRP steps, but the other does), a product of the formula:

is formed. The subsequent number of branches is reduced by 2^(h).

The present invention also concerns cross-linked polymers and gels, andprocesses for producing the same. By conducting the polymerizing stepwhich produces the present branched and/or hyperbranched (co)polymersfor a longer period of time, gelled polymers may be formed. For example,by increasing the amount or proportion of p-chloromethyl styrene in thereaction mixture (e.g., relative to solvent or other monomer(s)), thecross-link density may be increased and the reaction time may belowered.

(Typically, a polymerizing step in any aspect of the present inventionmay be conducted for a length of time sufficient to consume at least25%, preferably at least 50%,more preferably at least 75%, even morepreferably at least 80% and most preferably at least 90% of monomer.Alternatively, the present polymerizing step may be conducted for alength of time sufficient to render the reaction mixture too viscous tostir, mix or pump with the stirring, mixing or pumping means being used.However, the polymerizing step may generally be conducted for anydesired length of time.)

The present invention also encompasses graft or “comb” copolymers,prepared by sequential polymerizations. For example, a first (co)polymermay be prepared by conventional radical polymerization, then a second(or one or more further) (co)polymer chains or blocks may be graftedonto the first (co)polymer by ATRP; a first (co)polymer may be preparedby ATRP, then one or more further (co)polymer chains or blocks may begrafted onto the first (co)polymer by conventional radicalpolymerization; or the first (co)polymer may be prepared and the further(co)polymer chains or blocks may be grafted thereonto by: sequentialATRP's.

A combination of ATRP and one or more other polymerization methods canalso be used to prepare different blocks of a linear or star blockcopolymer (i.e., when extending one or several chains from a base(co)polymer). Alternatively, a combination of ATRP and one or more otherpolymerization methods can be used to prepare a “block homopolymer”, inwhich distinct blocks of a homopolymer having one or more differentproperties (e.g., tacticity) are prepared by different polymerizationprocesses. Such “block homopolymers” may exhibit microphase separation.

Thus, the present invention further concerns a method of preparing agraft or “comb” (co)polymer which includes the present ATRP process,which may comprise reacting a first (co)polymer having either aradically transferable X substituent (as defined above) or a group thatis readily converted (by known chemical methods) into a radicallytransferable substituent with a mixture of (i) transition metal compoundcapable of participating in a reversible redox cycle with the first(co)polymer, (ii) a ligand (as defined above) and (iii) one or moreradically polymerizable monomers (as defined above) to form a reactionmixture containing the graft or “comb” (co)polymer, then isolating theformed graft or “comb” (co)polymer from the reaction mixture. The methodmay further comprise the step of preparing the first (co)polymer byconventional radical, anionic, cationic or metathesis polymerization orby a first ATRP, in which at least one of the monomers has a R¹-R⁴substituent which is encompassed by the description of the “X” groupabove. Where the catalyst and/or initiator used to prepare the first(co)polymer (e.g., a Lewis acid used in conventional cationicpolymerization, a conventional metathesis catalyst having a metal-carbonmultiple :bond, a conventional organolithium reagent) may beincompatible with the chosen ATRP initiation/catalyst system, or mayproduce an incompatible intermediate, the process may further comprisethe step of deactivating or removing the catalyst and/or initiator usedto prepare the first (copolymer prior to the grafting step (i.e.,reacting the first (co)polymer with subsequent monomer(s) by ATRP).

Alternatively, the method of preparing a graft or “comb” (co)polymer maycomprise preparing a first (co)polymer by the present ATRP process, thengrafting a number of (co)polymer chains or blocks onto the first(co)polymer by forming the same number of covalent bonds between thefirst (co)polymer and one or more polymerizable monomers (e.g., byconventional radical polymerization, conventional anionicpolymerization, conventional cationic polymerization, conventionalmetathesis polymerization, or the present ATRP process) polymerizing thepolymerizable monomer(s) in accordance with the conventional or ATRPprocesses mentioned to form a reaction mixture containing the graft or“comb” (co)polymer, then isolating the formed graft or “comb”(co)polymer from the reaction mixture.

Preferably the X substituent on the first (co)polymer is Cl or Br.Examples of preferred monomers for the first (co)polymer thus includeallyl bromide, allyl chloride, vinyl chloride, 1- or 2- chloropropene,vinyl bromide, 1,1- or 1,2-dichloro- or dibromoethene, trichloro- ortribromoethylene, tetrachloro- or tetrabromoethylene, chloroprene,1-chlorobutadiene, 1- or 2-bromobutadiene, vinyl chloroacetate, vinyldichloroacetate, vinyl trichloroacetate, etc. More preferred monomersinclude vinyl chloride, vinyl bromide, vinyl chloroacetate andchloroprene. It may be necessary or desirable to hydrogenate (by knownmethods) the first (co)polymer (e.g., containing chloroprene units)prior to grafting by ATRP.

Thus, the present invention also encompasses graft or “comb”(co)polymers having a formula:

X_(f−e)R″—(M¹ _(i)—X)_(e)

X_(f−e)R″—[(M¹ _(i)M² _(j))—X]_(e)

X_(f−e)R″—[(M¹ _(i)M² _(j)M³ _(k))—X]_(e)

X_(f−e)R″—[(M¹ _(i)M² _(j)M³ _(k) . . . M^(u) _(l))—X]_(e)

X_(f−e)R″—[(M¹)_(p)—(M²)_(q)—X]_(e)

X_(f−e)R″—[(M¹)_(p)—(M²)_(q)—(M³)_(r)—X]_(e)

X_(f−e)R″—[(M¹)_(p)—(M²)_(q)—(M³)_(r)— . . . —(M^(u))_(s)—X]_(e)

where R″ is a first (co)polymer remainder from a first copolymer havinga formula RX_(f), f≧e; e is a number having an average of at least 2.5,preferably at least 3.0, more preferably at least 5.0, and mostpreferably.at least 8.0; X is as defined above (and is preferably ahalogen); M¹, M², M³, . . . up to M^(u) are each a radicallypolymerizable monomer (as defined above); p, q, r and s are selected toprovide weight or number average molecular weights for the correspondingblock is at least 100 g/mol, preferably at least 250 g/mol, morepreferably at least 500 g/mol and even more preferably at least 1,000g/mol; and i, j, k . . . up to l represent molar ratios of the radicallypolymerizable monomers M¹, M², M³, . . . up to M^(u). Thepolydispersity, average degree of polymerization and/or the maximumweight or number average molecular weight of the (co)polymer orcomponent thereof (e.g., base polymer or graft side-chain) may be asdescribed above.

Preferred graft copolymers include those in which the first (co)polymerincludes at least three units of vinyl chloride, vinyl bromide, or aC₂-C₃-alkenyl halo-C₁-C₂₀-alkanoate ester (e.g., vinyl chloroacetate).More preferred graft copolymers include those in which the first(co)polymer is an N-vinylpyrrolidone/vinyl chloroacetate copolymercontaining on average at least three units of vinyl chloroacetate perchain, in which polystyrene chains are grafted thereonto by ATRP usingthe chloroacetate moiety as initiator. Such graft copolymers areexpected to be useful to make, e.g., disposable contact lenses.

In the present copolymers, each of the blocks may have a number averagemolecular weight in accordance with the homopolymers described above.Thus, the present copolymers may have a molecular weight whichcorresponds to the number of blocks (or in the case of star polymers,the number of branches times the number of blocks) times the numberaverage molecular weight range for each block.

Polymers and copolymers produced by the present process havesurprisingly low polydispersities for (co)polymers produced by radicalpolymerization. Typically, the ratio of the weight average molecularweight to number average molecular weight (“M_(w)/M_(n)”) is ≦1.5,preferably ≦1.4, and can be as low as 1.10 or less.

Because the “living” (co)polymer chains retain an initiator fragment inaddition to an X or X′ as an end group or as a substituent in thepolymer chain, they may be considered end-functional or in-chain(multi)functional (co)polymers. Such (co)polymers may be used directlyor be converted to other functional groups for further reactions,including crosslinking, chain extension, reactive injection molding(RIM), and preparation of other types of polymers (such aspolyurethanes, polyimides, etc.).

The present invention provides the following advantages:

A larger number and wider variety of monomers can be polymerized byradical polymerization, relative to ionic and other chainpolymerizations;

Polymers and copolymers produced by the present process exhibit a lowpolydispersity (e.g., M_(w)/M_(n)≦1.5 preferably ≦1.4, more preferably≦1.25, and most preferably, ≦1.10), thus ensuring a greater degree ofuniformity, control and predictability in the (co)polymer properties;

One can select an initiator which provides an end group having the samestructure as the repeating polymer units (1-phenylethyl chloride asinitiator and styrene as monomer);

The present process provides high conversion of monomer and highinitiator efficiency;

The present process exhibits excellent “living” character, thusfacilitating the preparation of block copolymers which cannot be formedby ionic processes;

Polymers produced by the present process are well-defined and highlyuniform, comparable to polymers produced by living ionic polymerization;

End-functional initiators (e.g., containing COOH, OH, NO₂, N₃, SCN,etc., groups) can be used to provide an end-functional polymer in onepot, and/or polymer products with different functionalities at each end(e.g., in addition to one of the above groups at one end, acarbon-carbon double bond, epoxy, imino, amide, etc., group at anotherend);

The end functionality of the (co)polymers produced by the presentprocess (e.g., Cl, Br, I, CN, CO₂R) can be easily converted to otherfunctional groups (e.g., Cl, Br and I can be converted to OH or NH₂ byknown processes, CN or CO₂R can be hydrolyzed to form a carboxylic acidby known processes, and a carboxylic acid may be converted by knownprocesses to a carboxylic acid halide), thus facilitating their use inchain extension processes (e.g., to form long-chain polyamides,polyurethanes and/or polyesters);

In some cases (e.g., where “X” is Cl, Br and I), the end functionalityof the polymers produced by the present process can be reduced by knownmethods to provide end groups having the same structure as the repeatingpolymer units.

Even greater improvements can be realized by using (a) an amount of thecorresponding reduced or oxidized transition metal compound whichdeactivates at least part of the free radicals which may adverselyaffect polydispersity and molecular weight control/predictability and/or(b) polymerizing in a homogeneous system or in the presence of asolubilized initiating/catalytic system;

A wide variety of (co)polymers having various structures and topologies(e.g., block, random, graft, alternating, tapered (or “gradient”), star,“hyperbranched”, cross-linked and water-soluble copolymers andhydrogels) which may have certain desired properties or a certaindesired structure may be easily synthesized; and

Certain such (co)polymers may be prepared using water as a medium.

Other features of the present invention will become apparent in thecourse of the following descriptions of exemplary embodiments which aregiven for illustration of the invention, and are not intended to belimiting thereof.

EXAMPLES Example 1

The effect of air exposure upon heterogeneous ATRP of styrene. Thefollowing amounts of reagents were weighed into each of three glasstubes under an inert atmosphere in a nitrogen-filled dry box: 11.0 mg(4.31×10⁻² mmol) of [(bipy)CuCl]₂ (Kitagawa, S.; Munakata, M. Inorg.Chem. 1981, 20, 2261), 1.00 mL (0.909 g, 8.73 mmol) of dry, deinhibitedstyrene, and 6.0 μL (6.36 mg, 4.52×10⁻² mmol) of dry1-phenylethylchloride [1-PECl].

The first tube was sealed under vacuum without exposure to air.

The second tube was uncapped outside of the dry box and shaken whileexposed to ambient atmosphere for two minutes. The tube was thenattached to a vacuum line, the contents were frozen using liquidnitrogen, the tube was placed under vacuum for five minutes, thecontents were thawed, and then argon was let into the tube. This“freeze-pump-thaw” procedure was repeated before the tube was sealedunder vacuum, and insured that dioxygen was removed from thepolymerization solution.

The third tube was exposed to ambient atmosphere for 10 minutes andsubsequently sealed using the same procedure.

The three tubes were heated at 130° C. for 12 h using a thermostattedoil bath. Afterwards, the individual tubes were broken, and the contentswere dissolved in tetrahydrofuran [THF] and precipitated into CH₃OH.Volatile materials were removed from the polymer samples under vacuum.Molecular weights and polydispersities were measured using gelpermeation chromatography [GPC] relative to polystyrene standards.Results are shown in Table 1 below.

TABLE 1 Results of the air exposure experiments Time of Air ExposureYield M_(n) PDI None 100 18,200 1.61  2 min 70 13,200 1.59 10 min 6111,900 1.39

Example 2

General procedure for the homogeneous ATRP of styrene. The followingamounts of reagents were weighed into glass tubes under ambientatmosphere: 12.0 mg (8.37×10⁻² mmol) of CuBr, 1.00 mL (0.909 g, 8.73mmol) of deinhibited styrene, and 12.0 μL (16.3 mg, 8.8×10⁻² mmol) of1-phenylethylbromide [1-PEBr]. For polymerizations using dNbipy, 72.0 mg(0.175 mmol) of the ligand was added, for dTbipy, 47.0 mg (0.175 mmol)was added, and for dHbipy, 62.0 mg (0.175 mmol) was added. Two“freeze-pump-thaw” cycles (described above) were performed on thecontents of each tube in order to insure that dioxygen was removed fromthe polymerization solution. Each tube was sealed under vacuum.

The tubes were placed in an oil bath thermostatted at 100° C. At timedintervals, the tubes were removed from the oil bath and cooled to 0° C.using an ice bath in order to quench the polymerization. Afterwards, theindividual tubes were broken, and the contents were dissolved in 10.0 mlof THF. Catalyst could be removed by passing the polymer solutionthrough an activated alumina column. Percent conversion of each samplewas measured using gas chromatography, and molecular weights andpolydispersities were measured using GPC relative to polystyrenestandards. Results are shown in Tables 2 and 3 below.

TABLE 2 Molecular weight data for the homogeneous ATRP of styrene usingdTbipy as the ligand. Time % M_(n) PDI (min) Conversion (GPC) (GPC) 6014.5 1250 1.08 120 20 1610 1.09 181 28 2650 1.09 270 43 3880 1.08 303 494670 1.10 438 59 5700 1.08

TABLE 3 Molecular weight data for the homogeneous ATRP of styrene usingdHbipy as the ligand. Time % M_(n) PDI (min) Conversion (GPC) (GPC) 6031 2860 1.05 124 45 3710 1.04 180 58 6390 1.04 240 78 8780 1.05 390 909230 1.06

Example 3

General procedures for the determination of the effect of addedcopper(II) on homogeneous ATRP of styrene. dHbipy was prepared accordingto the procedure of Kramer et al (Angew. Chem., Intl. Ed. Engl. 1993,32, 703). dTbipy was prepared according to the procedure of Hadda andBozec (Polyhedron 1988, 7, 575). CuCl was purified according to theprocedure of Keller and Wycoff (Inorg. Synth. 1946, 2, 1).

Method 1: Weighed Addition of the Transition Metal Reagents

In a dry box, appropriate amounts of pure CuCl, pure CuCl₂, bipyridylligand, dry 1-PECl and 1,4-dimethoxybenzene added to a 100 mL Schlenkflask equipped with a magnetic stir bar. The flask was fitted with arubber septum, removed from the dry box, and attached to a Schlenk line.The appropriate amounts of dry, deinhibited styrene and high boilingsolvent were added to the flask, and the septum was fixed in place usingcopper wire. The flask, with the polymerization solution always under:an argon atmosphere, was heated at 130° C. using a thermostatted oilbath, and upon heating a homogeneous red-brown,solution formed. Aliquotsof the polymerization solution (2.00 mL) were removed at timed intervalsusing a purged syringe and dissolved in 10.0 ml of THF. Percentconversion of each sample was measured using gas chromatography, andmolecular weights and polydispersities were measured using GPC relativeto polystyrene standards.

Polymerization #1 (no CUCl₂):

8.5 mg (0.86 mmol) of CuCl

0.120 mL (0.91 mmol) of 1-PECl

46.6 mg (1.74 mmol) of dTbipy

20.0 mL (0.175 mol) of styrene

20.0 g of p-dimethoxybenzene

TABLE 4 Results of polymerization #1 Time % M_(n) PDI (min) Conversion(GPC) (GPC) 38 12 2,910 1.60 82 19 3,700 1.60 120 23 5,370 1.57 177 468,480 1.46 242 58 11,500 1.37 306 66 13,300 1.33 373 69 14,400 1.29 131893 19,000 1.22

Polymerization #2 (3 mol % CUCl₂):

8.9 mg (0.90 mmol) of Cucl

0.4 mg (0.03 mmol) of CuCl₂

0.120 mL (0.91 mmol) of 1-PECl

47.1 mg (1.75 mmol) of dTbipy

20.0 mL (0.175 mol) of styrene

20.0 g of p-dimethoxybenzene

TABLE 5 Results of polymerization #2 Time % M_(n) PDI (min) Conversion(GPC) (GPC) 37 0 0 — 85 8 1,870 1.44 123 22.5 3,280 1.41 194 30.5 4,4701.40 256 39 6,920 1.31 312 43 9,340 1.27 381 48 10,000 1.25 1321 7915,490 1.21 1762 83 15,300 1.21

Method 2: Addition of Stock Solutions of the Copper Reagents

The polymerizations were conducted as in the general procedurehomogeneous ATRP of styrene, except that stock solutions of thedipyridyl ligand with CuBr, and separately, CuBr₂ in styrene wereprepared and added to 1-PEBr in the glass tube before removal from thedry box and sealing.

Polymerization #1 (no CuBr₂):

4.5×10⁻² mmol of CuBr

6.2 μL (4.5×10⁻² mmol) of 1-PEBr

32.0 mg (9.0×10⁻² mmol) of dHbipy

0.5 mL (4.36 mol) of styrene

TABLE 6 Results of polymerization #1 Time % M_(n) PDI (min) Conversion(GPC) (GPC) 70 38 4,510 1.08 120 64 6,460 1.09 160 68 6,710 1.10 200 728,290 1.11 240 82 9,480 1.14 300 86 10,180 1.13

Polymerization #2 (1.0 mol % of CuBr₂):

4.5×10⁻² mmol of CuBr

4.5×10⁻⁴ mmol of CuBr₂

6.2 μL (4.5×10⁻² mol) of 1-PEBr

9.0×10⁻² mmol of dHbipy

0.5 mL (4.36 mol) of styrene

TABLE 7 Results of polymerization #2 Time % M_(n) PDI (min) Conversion(GPC) (GPC) 50 5 1210 1.07 105 18 2870 1.05 165 39 4950 1.06 174 40 49901.06 300 68 6470 1.07

Example 4 ATRP of Water-Soluble Monomers

General procedure for the polymerization of water soluble monomers.Under ambient conditions, a glass tube was charged with the appropriateamounts of copper(I) halide (unpurified), bipy, initiator, and monomer.Water, if used, was then added. Two “freeze-pump-thaw” cycles (describedabove) were performed on the contents of each tube in order to insurethat dioxygen was removed from the polymerization solution. Each tubewas sealed under vacuum, and then placed in a thermostatted oil bath at80° C. or 100° C. for 12 h. Afterwards, the individual tubes werebroken.

(a) P(NVP). For N-vinyl pyrrolidone, the contents were dissolved in 10.0ml of THF. Percent conversion of each sample was measured using gaschromatography.

Bulk Conditions:

12.1 mg (8.4×10⁻² mmol) of CuBr

28.1 mg (0.18 mmol) of bipy

4.0 μl (6.2 mg, 4.1×10⁻² mmol) of bromomethyl acetate

1.00 mL (0.980 g, 8.82 mmol) of N-vinyl pyrrolidone

Heated at 100° C. for 12 h

% Conversion=100

Aqueous conditions:

13.7 mg (9.6×10⁻² mmol) of CuBr

30.1 mg (0.19 mmol) of bipy

4.0 μl (6.2 mg, 4.1×10⁻² mmol) of bromomethyl acetate

1.00 mL (0.980 g, 8.82 mmol) of N-vinyl pyrrolidone

1.00 mL of water

Heated at 100° C. for 12 h

% Conversion=80

(b) P(acrylamide). For acrylamide, the contents were dissolved in 50 mLof water and precipitated into 200 mL of CH₃OH. The polymer was isolatedby filtration, and volatile materials were removed under vacuum.

Conditions:

10.7 mg (7.5×10⁻² mmol) of CuBr

39.3 mg (0.25 mmol) of bipy

8.0 μl (12.0 mg, 7.2×10⁻² mmol) of methyl-2-bromopropionate

1.018 g (14.3 mmol) of acrylamide

1.00 mL of water

Heated at 100° C. for 12 h.

Yield: 0.325 (32%) of a white solid

(c) P(HEMA). For 2-hydroxyethyl methacrylate, the contents weredissolved in 50 mL of dimethyl formamide [DMF] and precipitated into 200mL of diethyl ether. The solvent was decanted from the oily solid, andthe residue was dissolved in 25 mL of DMF. To this solution, 25 mL ofacetyl chloride was added and the solution was heated at reflux for 4 h.Then, 50 mL of THF was added and the solution was poured into 250 mL ofCH₃OH. The resulting suspension was isolated by centrifugation, and thematerial was repreciptated from 50 mL of THF using 250 mL of CH₃OH. Themolecular weight and polydispersity of the sample was measured using GPCrelative to polystyrene standards.

Conditions:

11.1 mg (2.1×10⁻² mol) of Cu(bipy)₂ ⁺ (PF₆)⁻

6.0 μl (8.0 mg, 4.1×10⁻² mmol) of ethyl-2-bromoisobutyrate

1.00 mL (1.07 g, 5.5 mmol) of 2-hydroxyethyl methacrylate

1.00 mL of water

Heated at 80° C. for 12 h.

Mn=17,400; PDI=1.60

Examples 5-8 Random Copolymers

ATRP allows preparation of random copolymers of a variety of monomersproviding a broad range of compositions, well controlled molecularweights and narrow molecular weight distributions.

Example 5 Preparation of Random Copolymers of Methyl Methacrylate andStyrene

(a) Copolymers Containing 20% Styrene

0.007 g of CuBr, 0.0089 g of 2,2′-bipyridyl and 0.067 ml ofethyl-2-bromoisobutyrate was added to a degassed mixture of styrene(0.25 ml) and methyl methacrylate (0.75 ml) and the reaction mixture washeated to 100° C. After 2.5 hrs. the polymerization was interrupted, andthe resulting polymer was precipitated on methanol and purified byreprecipitation from THF/methanol. The yield of the copolymer was 35%.

The composition of the copolymer was determined by NMR to be 20 mol. %styrene. Molecular weight, M_(n), of the copolymer was 11,000 andpolydispersity (Mw/Mn)=1.25, as obtained from GPC relative topolystyrene standards.

(b) Copolymers Containing 50% Styrene

0.007 g of CuBr, 0.0089 g of 2,2′-bipyridyl and 0.067 ml ofethyl-2-bromoisobutyrate was added to a degassed mixture of styrene (0.5ml) and methyl methacrylate (0.5 ml). The reaction mixture was heated to100° C. After 3.5 hrs., the polymerization was interrupted, and theresulting polymer was precipitated in methanol and purified byreprecipitation from THF/methanol. The yield of the copolymer was 18%.

The composition of the copolymer was determined by NMR to be 50% (bymoles) of styrene. Molecular weight, M_(n), of the copolymer was 9,000and polydispersity Mw/Mn=1.27, as obtained from GPC relative topolystyrene standards.

(c) Copolymers Containing 65% Styrene

0.007 g of CuBr, 0.0089 g of 2,2′-bipyridyl and 0.067 ml ofethyl-2-bromoisobutyrate was added to a degassed mixture of styrene(0.75 ml) and methyl methacrylate (0.25 ml). The reaction mixture washeated to 100° C. After 2.0 hrs., the polymerization was interrupted,and the resulting polymer was precipitated in methanol and purified byreprecipitation from THF/methanol. The yield of the copolymer was 16%.

The composition of the copolymer was determined by NMR to be 65% (bymoles) of styrene. Molecular weight, M_(n), of the copolymer was 6,000and polydispersity Mw/Mn=1.25, as obtained from GPC relative topolystyrene standards.

Example 6 Random Copolymerization Between Styrene (70 mol %) andAcrylonitrile (30 mol %)

2,2′-Bipyridyl (0.1781 g), dimethoxybenzene (20 g), and Cu(I) Cl (0.0376g) were added to a 100 ml flask, which was sealed with a rubber septumand copper wire. The flask was placed under vacuum and then back-filledwith argon. This was repeated two more times. Styrene (17.2 ml) andacrylonitrile (4.2 ml) were then added via syringe. The monomers hadbeen previously deinhibited by passing through a column of alumina anddegassed by bubbling argon through the monomer for fifteen minutes.1-Phenylethyl chloride (0.0534 g) was then added to the reaction mixtureby syringe, and the reaction was heated to 130° C. Samples were taken(0.5 ml each). Conversion was determined by ¹H NMR, and the Mn andpolydispersity (PD) determined by GPC. The samples were then purified bydissolution in THF and precipitation into methanol three times. Thepurified polymer was then evaluated for acrylonitrile content by ¹H NMR.The differences in monomer reactivities (reactivity ratio) may provide acompositional gradient. Table 8 lists the results.

TABLE 8 Time Conversion % (h) (%) M_(n) PD Acrylonitrile 2.0 27.0 81601.65 54.2 5.25 29.6 9797 1.51 35.6 8.0 39.4 11131 1.44 40.8 21.0 53.616248 1.31 34.1

Example 7 Preparation of Random Copolymer of Styrene and Methyl Acrylate

0.010 g of CuBr, 0.0322 g of 2,2′-bipyridyl and 0.010 ml ofethyl-2-bromoisobutyrate was added to a degassed mixture of methylacrylate (0.42 ml) and styrene (1.00 ml) and the reaction mixture washeated to 90° C. After 14 hrs., the polymerization was interrupted andthe resulting polymer was precipitated on methanol and purified byreprecipitation from THF/methanol. The yield of the copolymer was 87%.

The composition of the copolymer was determined by NMR to be 40% (bymoles) of, styrene. Molecular weight, M_(n), of the copolymer was 22,000and polydispersity Mw/Mn=1.18, as obtained from GPC relative topolystyrene standards. The monomer reactivity ratio may have provided acompositional gradient.

Example 8 Preparation of Random Copolymer of Methyl Methacrylate andButyl Acrylate

0.010 g of CuBr, 0.0322 g of 2,2′-bipyridyl and 0.010 ml ofethyl-2-bromoisobutyrate was added to a degassed mixture of methylmethacrylate (2.5 ml) and butyl acrylate (2.5 ml) and the reactionmixture was heated to 110° C. After 2.5 hrs., the polymerization wasinterrupted, and the resulting polymer was precipitated on methanol andpurified by reprecipitation from THF/methanol. The yield of thecopolymer was 53%.

The composition of the copolymer was determined by NMR to be 15% (bymoles) of butyl acrylate. Molecular weight, M_(n), of the copolymer was11,000 and polydispersity Mw/Mn=1.50, as obtained from GPC relative topolystyrene standards. The monomer reactivity ratio may have provided acompositional gradient.

Alternating and Partially Alternating Copolymers Example 9 AlternatingCopolymers Isobutylene (IB)/Methyl Acrylate (Molar Feed 3.5:1)

To 0.11 g (6.68×10⁻⁴ mole) 2,2′-bipyridyl and 0.036 g (2.34×10⁻⁴ mole)CuBr at −30° C. in a glass tube, were added 1.75 ml (2×10⁻² mole) IB,0.5 ml (0.55×10⁻² mole) methyl acrylate (MA) and 0.036 ml (2.34×10⁻⁴mole) 1-phenylethyl bromide under an argon atmosphere. The glass tubewas sealed under vacuum, and the reaction mixture was warmed at 50° C.for 48 hours. The reaction mixture was then dissolved in THF, andconversion of MA as determined by GC was 100%. The polymer was thenprecipitated in methanol (three times), filtered, dried at 60° C.undervacuum for 48 h and weighed. The content of IB in copolymer was51%, and M_(n)=4050, M_(w)/M_(n)=1.46 (M_(th)=3400). The % of IB in thecopolymer as determined by integration of methoxy and gem-dimethylregions of the ¹H-NMR spectrum was 44%. The tacticity of the alternatingcopolymer as calculated from the signals of methoxy protons according tothe method described by Kuntz (J. Polym. Sci. Polym. Chem. 16, 1747,1978) is rr/mr/mm=46/28/26. The glass transition temperature of productas determined by DSC was −28° C.

Example 10 IB/MA Copolymer (Molar Feed 1:1)

To 0.055 g (3.5×10⁻⁴ mole) 2,2′-bipyridyl and 0.017 g (1.17×10⁻⁴ mole)CuBr at −30° C. in a glass tube, were added 0.5 ml (0.55×10⁻² mole) IB,0.5 ml (0.55×10⁻² mole) methyl acrylate and 0.016 ml (1.17×10⁻⁴ mole)1-phenylethyl bromide under argon atmosphere. The glass tube was sealedunder vacuum and the reaction mixture was warmed at 50° C. for 24 hours.The reaction mixture was then dissolved in THF, and conversion of MA asdetermined by GC was 100%. The polymer was than precipitated in methanol(three times), filtered, dried at 60° C. under vacuum for 48 h andweighed. The content of IB in copolymer was 28% and Mn=6400,M_(w)/M_(n)=1.52 (M_(th)=6500). The % of IB in copolymer determined byintegration of methoxy and gem-dimethyl region of the ¹H-NMR spectrumaccording to the method described by Kuntz was 26%. The glass transitiontemperature of the product as determined by DSC was −24° C.

Example 11 IB/MA Copolymer (Molar Feed 1:3)

To 0.11 g (6.68×10⁻⁴ mole) 2,2′-bipyridyl and 0.036 g (2.34×10⁻⁴ mole)CuBr at −30° C. in a glass tube, were added 0.5 ml (0.55×10⁻² mole) IB,1.5 ml (1.65×10⁻² mole) methyl acrylate and 0.036 ml (2.34×10⁻⁴ mole)1-phenylethyl bromide under argon atmosphere. The glass tube was sealedunder vacuum and the reaction mixture warmed at 50° C. for 48 hours. Thereaction mixture was then dissolved in THF, and the conversion of MA asdetermined by GC was 100%. The polymer was then precipitated in methanol(three times), filtered, dried at 60° C. under vacuum for 48 h andweighed. The content of IB in the copolymer was 25%, and Mn=7570,M_(w)/M_(n)=1.58 (M_(th)=7400). The % of IB in copolymer as determinedby integration of methoxy and gem-dimethyl region of the ¹H-NMR spectrumaccording to the method described by Kuntz was 24%. The glass transitiontemperature of the product as determined by DSC was −15° C.

Example 12 Alternating Copolymers of Isobutyl Vinyl Ether (IBVE)/MethylAcrylate (1:1)

To 0.055 g (3.51×10⁻⁴ mole) 2,2′-bipyridyl and 0.017 g (1.17×10⁻⁴ mole)CuBr in a glass tube, were added 0.6 ml (0.55×10⁻² mole) IBVE, 0.5 ml(0.55×10⁻² mole) methyl acrylate and 0.017 ml (1.17×10⁻⁴ mole)1-phenylethyl bromide under argon atmosphere. The glass tube was sealedunder vacuum, and the reaction mixture was warmed at 50° C. for 12hours. The reaction mixture was then dissolved in THF, and theconversion of MA and IBVE as determined by GC were 100%. The polymer wasthen precipitated in methanol (three times), filtered, dried at 60° C.under vacuum for 48 h and weighed. The content of IBVE in copolymer was51%, and M_(n)=8110, M_(w)/M_(n)=1.54 (M_(th)=8700). The glasstransition temperature of the product as determined by DSC was −31.3° C.

Example 13 Copolymers of Isobutyl Vinyl Ether/Methyl Acrylate (3:1)

To 0.11 g (6.68×10⁻⁴ mole) 2,2′-bipyridyl and 0.036 g (2.34×10⁻⁴ mole)CuBr in a glass tube, were added 1.8 ml (1.65×10⁻² mole) IBVE, 0.5 ml(0.55×10⁻² mole) methyl acrylate and 0.034 ml (2.34×10⁻⁴ mole)1-phenylethyl bromide under argon atmosphere. The glass tube was sealedunder vacuum, and the reaction mixture was warmed at 50° C. for 12hours. The reaction mixture was then dissolved in THF, and theconversion of MA and IBVE as determined by GC were 100%. The polymer wasthen precipitated in methanol (three times), filtered, dried at 60° C.under vacuum for 48 h and weighed. The content of IBVE in the copolymerwas 75%, and Mn=8710, M_(w)/M_(n)=2.00 (M_(th)=9090). The glasstransition temperatures of the product as determined by DSC were −44.3°C. and 7.1° C.

Example 14 Copolymers of Isobutyl Vinyl Ether/Methyl Acrylate (1:3)

To 0.11 g (6.68×10⁻⁴ mole) 2,2′-bipyridyl and 0.036 g (2.34×10⁻⁴ mole)CuBr in a glass tube, were added 0.6 ml (0.55×10⁻² mole) IBVE, 1.5 ml(1.65×10⁻² mole) methyl acrylate and 0.034 ml (2.34×10⁻⁴ mole)1-phenylethyl bromide under argon atmosphere. The glass tube was sealedunder vacuum, and the reaction mixture was warmed at 50° C. for 12hours. The reaction mixture was then dissolved in THF, and theconversion of MA and IBVE as determined by GC were 100%. The polymer wasthen precipitated in methanol (three times), filtered, dried at 60° C.under vacuum for 48 h and weighed. The content of IBVE in the copolymerwas 25%, and M_(n)=7860, M_(w)/M_(n)=1.90 (M_(th)=8400). The glasstransition temperatures of the product as determined by DSC were at−31.0° C. and 5.6° C.

Periodic Copolymers Example 15

Under an argon atmosphere, 11.1 mL of styrene (9.6×10⁻² mole) was addedto. 0.097 g (6×10⁻⁴ mole) of 2,2′-bipyridyl and 0.020 g (2×10⁻⁴ mole)CuCl in a 50 mL glass flask. The initiator 0.030 mL (2×10⁻⁴ mole)1-phenylethyl chloride was then added via syringe. The flask was thenimmersed in oil MOV bath at 130° C. At various time intervals, samplesfrom the reaction mixture were transferred to an NMR tube, and theconversion of styrene was determined.

Thereafter, 1.5 eq. of maleic anhydride (0.03 g, 3×10⁻⁴ mole) in benzene(4 mL) was injected into the flask at times of 20, 40, 60 and 80%conversion of styrene. After 25 hours, the reaction mixture was cooledto room temperature, and 15 mL of THF was added to the samples todissolve the polymers. The conversion of styrene by measuring residualmonomer was 95%.

The polymer was precipitated in dry hexane, filtered, dried at 60° C.under vacuum for 48 h and weighed. The product had a M_(n)=47500 andM_(w)/M_(n)=1.12 (M_(th)=50,000). The content of maleic anhydride wasdetermined by IR spectroscopy, and corresponded to the introducedamount.

Gradient Copolymers Example 16 Preparation of a Methyl Acrylate/MethylMethacrylate Gradient Copolymer

0.029 g of CuBr, 0.096 g of 2,2′-bipyridyl and 0.030 ml ofethyl-2-bromoisobutyrate were added to a degassed solution of methylacrylate (2.5 ml) and methyl methacrylate (2.0 ml) in ethyl acetate (2.0ml). The reaction mixture was thermostated at 90° C. and samples werewithdrawn after 3.0 hr, 5 hr, 7 hr and 23 hr. From the composition dataobtained from NMR measurements of these samples and from molecularweights evaluation from GPC measurements relative to polystyrenestandards, the compositional gradient along the chain of the finalcopolymer was calculated (FIGS. 3A-B). The final polymer (at 96%conversion) was purified by reprecipitation from methanol/THF.

Example 17

0.125 g of CuBr, 0.407 g of 2,2′-bipyridyl and 0.118 ml ofethyl-2-bromoisobutyrate was added to a degassed mixture of methylacrylate (3.8 ml) and methyl methacrylate (4.8 ml). The reaction mixturewas thermostated at 80° C. and samples were withdrawn after 0.5 hr, 1 hrand 1.5 hr. From the composition data obtained from NMR measurements ofthese samples and from molecular weights evaluation from GPCmeasurements relative to polystyrene standards, the compositionalgradient along the chain of the final copolymer was calculated (FIGS.4A-B). The final polymer (at 88% conv.) was purified by reprecipitationfrom methanol/THF.

Example 18 Preparation of a Styrene/Methyl Methacrylate GradientCopolymer

0.063 g of CuBr, 0.205 g of 2,2′-bipyridyl and 0.064 ml ofethyl-2-bromoisobutyrate was added to 5 ml of styrene and the mixturewas heated at 110° C. A mixture of styrene (5 ml) and methylmethacrylate (5 ml) was added at a rate of addition of 0.1 ml/min,followed by 10 ml of methyl methacrylate added at the same rate. Sampleswere withdrawn at certain time periods, and from the composition dataobtained from NMR measurements of these samples and from GPC measurementof the molecular weights relative to polystyrene standards, thecompositional gradient along the chain of the final copolymer wascalculated (FIGS. 5A-B). The final polymer (2.34 g) was purified byreprecipitation from methanol/THF. DSC measurements of the finalcopolymer show a single glass transition with T_(g)=106° C.

Example 19 Preparation of Methyl Acrylate/Methyl Methacrylate GradientCopolymer

0.107 g of CuBr, 0.349 g of 2,2′-bipyridyl and 0.109 ml ofethyl-2-bromoisobutyrate was added to a mixture of methyl acrylate (5ml) and methyl methacrylate (10 ml), and the reaction mixture was heatedto 90° C. Methyl acrylate (20 ml) was added to the reaction mixture at arate of addition of 0.1 ml/min. Samples were withdrawn at certain timeperiods, and from the composition data obtained from NMR measurements ofthese samples and from GPC measurement of the molecular weights relativeto polystyrene standards, the compositional gradient along the chain ofthe final copolymer was calculated (FIGS. 6A-B). The final polymer (3.15g) was purified by reprecipitation from methanol/THF. DSC measurementsof the final copolymer show a single glass transition with T_(g)=52° C.

Example 20 Preparation of Methyl Acrylate/Styrene Gradient Copolymerswith Varying Gradient of Composition

0.063 g of CuBr, 0.205 g of 2,2′-bipyridyl and 0.64 ml ofethyl-2-bromoisobutyrate was added to 10 ml of styrene and the reactionmixture was heated to 95° C. Methyl acrylate was added to the reactionmixture at a rate of addition of 0.1 ml/min such that the final reactionmixture contained 90% of methyl methacrylate. Samples were withdrawn atcertain time periods and from the composition data obtained from NMRmeasurements of these samples and from GPC measurement of the molecularweights relative to polystyrene standards, the compositional gradientalong the chain of the final copolymer was calculated (FIGS. 7A-B). Thefinal polymer (1.98 g) was purified by reprecipitation frommethanol/THF. DSC measurements of the final copolymer show a singleglass transition with T_(g)=58° C.

In a separate experiment, 0.063 g of CuBr, 0.205 g of 2,2′-bipyridyl and0.64 ml of ethyl-2-bromoisobutyrate was added to 10 ml of styrene andthe reaction mixture was heated to 95° C. Methyl acrylate was added tothe reaction mixture at a rate of addition of 0.085 ml/min such that thefinal reaction mixture contained 90% of methyl methacrylate. Sampleswere withdrawn at certain time periods. From the composition dataobtained from NMR measurements of these samples and from GPC measurementof the molecular weights relative to polystyrene standards, thecompositional gradient along the chain of the final copolymer wascalculated (FIGS. 8A-B). The final polymer (1.94 g) was purified byreprecipitation from methanol/THF. DSC measurements of the finalcopolymer show a single glass transition with T_(g)=72° C.

In a third experiment, 0.063 g of CuBr, 0.205 g of 2,2′-bipyridyl and0.64 ml of ethyl-2-bromoisobutyrate was added to 10 ml of styrene andthe reaction mixture was heated to 95° C. Methyl acrylate was added tothe reaction mixture at a rate of addition of 0.05 ml/min such that thefinal reaction mixture contained 90% of methyl methacrylate. Sampleswere withdrawn at certain time periods. From the composition dataobtained from NMR measurements of these samples and from GPC measurementof the molecular weights relative to polystyrene standards, thecompositional gradient along the chain of the final copolymer wascalculated (FIGS. 9A-B). The final polymer (3.08 g) was purified byreprecipitation from methanol/THF. DSC measurements of the finalcopolymer show a single glass transition with T_(g)=58° C.

Example 21 Branched and Hyperbranched Polymers

Homopolymerizations were performed as follows: Typically,p-chloromethylstyrene, p-CMS, was polymerized in the presence of CuCl(1% relative to PCS) and 2,2′-bipyridyl (3%), at 110° C., under oxygenfree conditions, i.e., argon atmosphere. p-Chloromethylstyrene was addedto a flask containing CuCl/bipyridyl. Immediately upon addition ofp-CMS, a deep red, slightly heterogeneous solution was obtained. Heatingresulted in the color of the solution changing from red to green withinfifteen minutes of heating.

After a period of time the reaction was stopped and the sample dissolvedin THF. Conversion was determined by ¹H NMR, and was found to be greaterthan 80%. The samples showed almost no observable change in viscosity atthe reaction temperature, but cooling to room temperature resulted inthe sample becoming solid. The green copper(II) material was removed bypassing the mixture through a column of alumina. Unprecipitated sampleswere analyzed by GPC relative to polystyrene standards. The polymer wasthen purified by precipitation into methanol from THF. These sampleswere then analyzed by ¹H NMR to determine molecular weight. Table 9outlines experimental results. All yields were >70%.

TABLE 9 Homopolymerization of p-Chloromethylstyrene in the Presence ofCu (I) and 2,2′-Bipyridyl^(a) Time Conversion Temperature (h) (%)^(c)M_(n) ^(d) M_(n) ^(e) M_(w)/M_(n) ^(e) M_(n) ^(f) 125° C. 0.5 67 19001160 1.8 1070 ″ 1.0 75 2250 1780 2.1 1870 ″ 1.5 90 2940 2410 2.1 2480 ″2.0 92 6280 2510 2.5 2750 110° C.^(b) 24.0 96 2420 2100 1.3 — ^(a)Bulkpolymerization, [M]_(o) = 7.04 M, [CuCl]_(o) = 0.07 M, [bipy]_(o) = 0.21M. ^(b)Solution polymerization in benzene, [M] = 3.52 M, [CuCl]_(o) =0.035 M, [bipy]_(o) = 0.11 M. ^(c)Conversion based on consumption ofdouble bonds. ^(d)M_(n) determined by ¹H NMR after precipitation.^(e)M_(n), M_(w) determined of entire sample, prior to precipitation, byGPC, using linear polystyrene standards. ^(f)M_(n) by GPC, using linearpolystyrene standards, after precipitation into methanol/brine.

Copolymerizations were carried out as follows: Styrene (18.18 g, 20 ml)was polymerized in a 50% w/v solution using p-dimethoxybenzene (20 g) assolvent. The amount of p-chloromethylstyrene was 2% (0.4 ml). The molarratio of p-chloromethylstyrene/CuCl (0.2594 g)/2,2′-bipyridyl (1.287 g)was 1:1:3. The solids were placed in a flask with a rubber septum andmagnetic stirrer, and degassed three times by vacuum and back fillingwith argon. Degassed monomer was added via syringe. The appropriateamount of p-chloromethyl-styrene was then added via syringe. Thereaction was heated to 130° C. The reaction was quenched byprecipitation into methanol. After 15 hours, conversion was 94.3% asdetermined by ¹H NMR. Yield was 76%.

The sample was evaluated by SEC using relative calibration, and found tohave Mn=13400 and M_(w)=75000. By universal calibration, in conjunctionwith light scattering, the M_(n)=31,600 and M_(w)=164,500.

Methyl methacrylate (20 ml, 18.72 g) was used in place of styrene. Thereaction, was run for 2 hours at 100° C. M_(n,SEC)=44,700 andM_(w,SEC)=112,400. M_(n)=58,700 (universal calibration), M_(w)=141,200(light scattering).

Cross-Linked Polymers and Gels Example 22

Styrene (9.09 g, 10 ml) was polymerized in a 50% (w/vol.) solution usingp-dimethoxybenzene (10 g) as solvent. The amount ofp-chloromethylstyrene was 2% (0.2 ml). The molar ratio ofp-chloromethylstyrene/CuCl (0.1297 g)/2,2′-bipyridyl (0.6453 g) was1:1:3. The solids were placed in a flask with a rubber septum andmagnetic stirrer, and degassed three times by vacuum and back fillingwith argon. Degassed monomer was added via syringe.p-Chloromethylstyrene was then added via syringe. The reaction washeated to 130° C. The reaction was quenched by precipitation intomethanol. After 64.5 hours, conversion was 94.3% as determined by ¹HNMR. Yield was 90%. A cloudy polymer solution was made in THF, but couldnot be passed through a 0.45 micron PTFE filter. Upon placing thesolution in a centrifuge for 26 hours at 7000 rpm, the solution wasclear with a slight layer of solid material at the bottom of the vial.The solution was passed through a 0.45 micron PTFE filter.M_(n)=118,000, M_(w)/M_(n)=3.74.

Example 23

Styrene (9.09 g, 10 ml) was polymerized in a 50% (w/vol.) solution usingp-dimethoxybenzene (10 g) as solvent. The amount of p-CMS was 10% (0.2ml). The molar ratio of p-CMS/CuCl (0.1297 g)/2,2′-bipyridyl (0.6453 g)was 1:1:3. The solids were placed in a flask with a rubber septum andmagnetic stirrer, and degassed three times by vacuum and back fillingwith argon. Degassed monomer was added via syringe. p-Chloromethylstyrene,was then added via syringe. The reaction was heated to 130° C.The reaction was quenched by precipitation into methanol. After 24hours, conversion was 94.3% as determined by ¹H NMR. Yield was >90%. Thepolymer was stirred in THF but could not be dissolved. The polymersample was placed in a soxhlet apparatus under refluxing THF to removecopper salts.

The obtained sample was placed in THF and allowed to come toequilibrium. The gel was determined to have an equilibrium THF contentof 89%.

Example 24 Difunctional Polymers

Polystyrene with two bromine or azide end groups were synthesized.

(A) α,ω-Dibromopolystyrene:

Styrene (18.18 g, 20 ml) was polymerized in a 50% (w/vol.) solutionusing p-dimethoxybenzene (20 g) as solvent. α,α′-Dibromo-p-xylene (1.848g) was used as the initiator. The molar ratio ofα,α′-Dibromo-p-xylene/styrene/CuBr (1.00 g)/2,2′-bipyridyl (3.28 g) was1:1:3. The solids were placed in a flask with a rubber septum andmagnetic stirrer, and degassed three times by vacuum and back fillingwith argon. Degassed monomer was added via syringe. The reaction washeated to 110° C. After 5.5 hours conversion was >95% as determined by¹H NMR. The reaction was quenched by precipitation into methanol. Yieldwas >90%. The polymer was redissolved in THF and precipitated intomethanol three times. The polymer sample was dried under vacuum at roomtemperature overnight. Mn, as determined by comparison of the methineprotons adjacent to bromine and the aliphatic protons, was 2340. SEC,Mn=2440.

(B) α,ω-Diazidopolystyrene:

A sample of the above α,ω-dibromopolystyrene (5.0 g) was dissolved indry THF (20 ml) in the presence of tetrabutyl ammonium fluoride (1 mmolF⁻/g) on silica gel (6.15 g). Trimethylsilyl azide (0.706 g, 0.81 ml)was then added via syringe. The solution was stirred for 16 hours underargon. ¹H NMR showed complete conversion of the methine protons adjacentto bromine to being adjacent to N₃. M_(n), by ¹H NMR, was 2340. Infraredspectroscopy showed a peak at 2080 cm⁻¹, which corresponds to the azidefunctional group.

A sample of the α,ω-diazidopolystyrene (4.7 mg) was placed in a DSCsample pan and was heated to 250° C. and held for 15 minutes. A seriesof endo and exothermic peaks were seen starting at 215° C. The samplewas allowed to cool and then dissolved in THF. The solution was injectedinto a SEC instrument. The Mn was 6500, a 250% increase in molecularweight. The distribution was broad, however.

Example 25 Water Swellable Polymers

(A): NVP/VAc-Cl Polymer:

N-vinylpyrrolidinone (50 ml, 48.07 g), vinyl chloroacetate (0.26 g, 0.25ml), and AIBN (0.7102 g) were combined in a 300 ml three-neck,round-bottom flask. The monomers were degassed by bubbling argon throughthe mixture. The mixture was heated to 60° C. for 1 h. The resultingsolid polymer was allowed to cool and then dissolved in THF. Thesolution was precipitated into hexanes, and the resulting polymerfiltered and dried at 70° C. under vacuum for three days.

(B): Hydrogel A:

The NVP/VAc-Cl polymer (5.0 g) of Example 25(A) was dissolved in styrene(20 ml), in the presence of CuCl (0.0411 g) and4,4′-di-t-butyl-2,2′-bipyridyl (0.2224 g), under oxygen free conditions.The reaction mixture was heated to 130° C. After 30 minutes, thereaction mixture became gelatinous. The mixture was dissolved in DMF andprecipitated into water. A gel-like mass was obtained and filtered. Theresulting solid was a gel weighing 20.0 g. The gel was dried over P₂O₅at 70° C. under vacuum for 2.5 days. Yield 4.0 g.

C: Hydropel B:

The NVP/VAc-Cl polymer (5.0 g) of Example 25(A) was dissolved in styrene(20 ml), in the presence of CuCl (0.0041 g) and4,4′-di-t-butyl-2,2′-bipyridyl (0.0222 g), under oxygen free conditions.The reaction mixture was heated to 130° C. After two hours, the reactionmixture became gelatinous. The reaction was stirred for three more hoursuntil the mixture was so viscous that the magnetic stir bar did notturn. The mixture was dissolved in DMF and precipitated into water. Agel-like mass was obtained and filtered. The resulting solid was a gelhaving a mass of 20.0 g. The gel was dried over P₂O₅ at 70° C. undervacuum for 2.5 days. Yield 4.0 g.

(D): Macromonomers of Styrene

(i): Synthesis of Polystyrene with a Vinyl Acetate End Group(VAc-Styrene)

5K Polystyrene:

Cu(I)Cl (0.5188 g) and 2,2′-bipyridyl (2.40 g) were added to a 100 mlround bottom flask and sealed with rubber septum. The contents of theflask were placed under vacuum, then backfilled with argon. This wasrepeated two additional times. Diphenyl ether (30.0 ml), deinhibitedstyrene (30.0 ml) and vinyl chloroacetate (0.53 ml), all of which werepreviously degassed by bubbling argon through the liquids, were added tothe flask via syringe. The reaction mixture was then heated to 130° C.for 6 hours. The reaction mixture was then transferred into methanol toprecipitate the formed polymer. The precipitate was then twicereprecipitated from THF into methanol. The isolated white powder wasthen dried under vacuum at room temperature. Yield: 21.68 g (77.4%).GPC: M_(n)=4400, PD=1.22.

10K Polystyrene:

Cu(I)Cl (0.5188 g) and 2,2′-bipyridyl (2.40 g) were added to a 250 mlround bottom flask and sealed with a rubber septum. The contents of theflask were placed under vacuum, then backfilled with argon. This wasrepeated two additional times. Diphenyl ether, (60.0 ml), deinhibitedstyrene (60.0 ml) and vinyl chloroacetate (0.53 ml), all of which werepreviously degassed by bubbling argon through the liquids, were added tothe flask via syringe. The reaction mixture was then heated to 130° C.for 24 hours. The reaction mixture was then transferred into methanol toprecipitate the formed polymer. The precipitate was then twicereprecipitated from THF into methanol. The isolated white powder wasthen dried under vacuum at room temperature. Yield: 44.36 g (81.3%).GPC: M_(n)=10,500, PD=1.25.

(ii): Synthesis of Water Swellable Polymers Copolymerization of N-VinylPyrrolidinone (75 wt. %) with VAc-Styrene (Mn=4400; 25 wt. %):

AIBN (0.0106 g) and VAc-styrene (2.50 g) were added to a 50 ml roundbottom flask and sealed with a rubber septum. The contents of the flaskwere placed under vacuum and backfilled with argon three times.Previously degassed DMSO (20.0 ml) and N-vinyl pyrrolidinone (7.5 ml)were added to the flask by syringe. The reaction was then heated to 60°C. for 20 hours. A highly viscous fluid was obtained and diluted withDMF (30.0 ml). The reaction mixture was precipitated into water. The 20precipitate was a swollen solid. This was filtered and dried undervacuum at 70° C. to produce the obtained polymer. The obtained polymerwas placed in a water bath for 3 days. The equilibrium water content was89%.

Copolymerization of N-Vinyl Pyrrolidinone (75 wt. %) with VAc-Styrene(Mn=10500, 25 wt. %)

AIBN (0.0106 g) and VAc-Styrene (2.50 g) were added to a 50 ml roundbottom flask and sealed with a rubber septum. The contents of the flaskwere placed under vacuum and backfilled with argon three times.Previously degassed DMSO (20.0 ml) and N-vinyl pyrrolidinone (7.5 ml)were added to the flask by syringe. The reaction was then heated to 60°C. for 20 hours. A highly viscous fluid was obtained and diluted withDMF (30.0 ml). The reaction mixture was precipitated into water. Theprecipitate was a white, jelly-like mass. The liquid was decanted, theprecipitate was air-dried overnight, and then dried under vacuum at 70°C. to produce the obtained polymer. M_(n)=116,000; PD=2.6.

After placing in a water bath for 3 days, the equilibrium water contentwas determined to be 89%.

Example 26 Thiocyanate Transfer Polymerizations

It has been previously reported that thiocyanate (SCN) is transferredfrom Cu(SCN)₂ to an alkyl radical at roughly the same rate as chloridefrom CuCl₂ (Kochi et al, J. Am. Chem. Soc., 94, 856, 1972).

A 3:1:1 molar ratio of ligand (2,2′-bipyridyl [bipy] or4,4′-di-n-heptyl-2,2′-bipyridyl [dHbipy]) to initiator (PhCH₂SCN) totransition metal compound (CuSCN) was used for each polymerization. Theinitiator system components were weighed and combined in air underambient conditions. The reactions were run in bulk according to theprocedure of Example 4, but at 120° C.

Reactions employing bipy were very viscous after 5 h, at which time theywere cooled to room temperature. Reactions employing dHbipy were notviscous after 5 h, and were therefore heated for 24 h before cooling toroom temperature. Results are shown in Table 10 below.

TABLE 10 Ligand M/I % Conv. M_(n) PDI bipy 193 39 158,300 1.61 bipy 38643 149,100 1.75 dHbipy 193 86 28,100 2.10 dHbipy 386 89 49,500 1.89

where “M/I” is the monomer/initiator ratio, “% Conv.” refers to thepercent conversion, and “PDI” refers to the polydispersity.

The bipy reactions showed less than optimal molecular weight control,but the dHbipy reactions showed excellent molecular weight control. Itis believed that PDI can be improved further by increasing the amount orconcentration of Cu(II) at the beginning of polymerization.

Example 27 Synthesis of Comb-shaped PSt

The macro ATRP initiator, poly(p-chloromethylstyrene), PCMS, wassynthesized by polymerizing p-chloromethylstyrene (0.02 mol) in benzene(50%) at 60° C. for 24 hours using ICH₂CN (0.0023 mol) and AIBN (0.0006mol). Yield: 92%. M_(n)=1150, M_(w)/M_(n)=1.20.

Subsequently, a degassed solution containing St (0.012 mol), purifiedPVBC (9.6×10⁻⁵ mol), CuCl (1.5×10⁻⁴ mol) and bipy (4.5×10⁻⁴ mol) washeated at 130° C. for 18 hrs. Comb-shaped PSt was obtained (yield=95%).M_(n)=18500, M_(w)/M_(n)=1.40. At lower initial concentrations of PCMS,higher molecular weight comb-shaped polystyrenes were formed(M_(n)=40,000 and 80,000 g/mol, as compared to linear polystyrenestandards, cf. the first three entries in Table 15).

Example 28 Synthesis of PVAc-g-PSt

Vinyl acetate end-capped PSt (PSt-VAc) was synthesized by polymerizingSt (0.019 mol) in bulk at 130° C. for 18 h using ClCH₂COOCH═CH2 (0.0018mol), CuCl (0.0018 mol) and bipy (0.0054 mol). Yield: 95%. Mn=1500,M_(w)/M_(n)=1.35.

Subsequently, a degassed solution containing vinyl acetate (5.8×10⁻³mol), purified PSt-VAc (6.67×10⁻⁵ mol) and AIBN (1×10⁻⁴ mol) in ethylacetate was heated at 60° C. for 48 h (ca. 85% conversion ofmacromonomer). Final grafting copolymer composition: Mn=54500,M_(w)/M_(n)=1.70.

Example 29 End-Functional Polymers

One of the advantages of ATRP process is that one can synthesizewell-defined end-functional polymers by using functional alkyl halidesand transition metal species (Scheme 4).

Tables 11 and 12 report the characterization data of ATRP's of St usingvarious functional alkyl halides as initiators under typical ATRPexperimental conditions.

From Table 11, it appears that acid-containing alkyl halides give riseto relatively uncontrolled polymers (e.g., limited conversions, highermolecular weights than expected, and relatively broad molecular weightdistributions). This suggests that CuCl may react with these alkylhalides with formation of side products which disturb the “living” ATRPprocess.

Using 3-chloro-3-methyl-1-butyne, the monomer conversion was almostquantitative. However, the experimental molecular weight is ca. 3 timesas high as expected, and the polydispersity is as high as 1.95. Thissuggests that initiation is slow and the triple bond might also beattacked by the forming radicals.

In addition, using 2-(bromomethyl)naphthalene and9-(chloromethyl)anthracene as initiators, the polymers obtained showedproperties as good as polymers obtained by using 1-alkyl-2-phenylethylhalide initiators. However, 1,8-bis(bromomethyl)naphthalene does notseem to be as efficient an ATRP initiator as 2-(bromomethyl)naphthaleneand 9-(chloromethyl)anthracene under the same conditions.

More importantly, several Pst macromonomers containing polymerizabledouble bonds can be obtained in a controlled manner (Table 11). The ¹HNMR spectrum of Pst initiated with vinyl chloroacetate in the presenceof 1 molar equiv. of CuCl and 3 molar equiv. of bipy at 130° C. showssignals at 4.0 to 5.5 ppm, assigned to vinylic end-groups. A comparisonof the integration of the vinylic protons with the protons in thebackbone gives a molecular weight similar to the molecular weightobtained from SEC; i.e., a functionality close to 0.90. This suggeststhat the double bond is unreactive towards a minute amount of St typeradicals during ATRP of St.

TABLE 11 ATRP Synthesis of End-Functional Polymers^(a) RX CuX Conv. %M_(n,th.) ^(b) M_(n,) SEC M_(w)/M_(n) ClCH₂—COOH CuCl 60 3000 12500 1.50HC≡CC(CH₃)₂Cl CuCl 95 4800 14100 1.90 ClCH₂—CONH₂ CuCl 70 3500 213001.70

CuCl 92 4140 6730 1.35

CuBr 96 1200 1010 1.35 H CuBr 99 5260 4300 1.25

CuBr 75 1180 820 1.25 BrCH₂—CH═CH₂ CuBr 99 5260 6500 1.23 ″ CuBr 99 1000970 1.23 ClCH₂—COOCH═CH₂ CuCl 95 1000 1500 1.35 ″ CuCl 98 3000 3150 1.30″ CuCl 99 5000 5500 1.30 CH₃CHBr—COOCH₂CH═CH₂ CuBr 90 4730 4580 1.40^(a)Polymerization conditions: molar ratio of RX/CuX/Bpy: 1/1/3; temp:Cl-ATRP, 130° C.; Br-ATRP, 110° C. ^(b)Calculated based on M_(n) = M_(o)× (D[M]/[RX]_(o)).

Example 30 Sequential Block Copolymerization

ATRP can also be successfully used to produce well-defined di- andtri-block copolymers by means of sequential addition technique.

As seen in Table 12, di- and tri-block copolymers of St and MA obtainedare very well defined, regardless of monomer addition order. Themolecular weights are close to theoretical, and molecular weightdistributions remain very narrow, M_(w)/M_(n) from ˜1.0 to ˜1.25. SECtraces show that almost no first polymer contaminates the final blockcopolymer.

DSC measurements of several samples in Table 12 were also carried out.There appears to be two glass transition temperatures around 30:0 and100° C., very close to the Tg's of PMA and PSt, respectively. NMRanalysis of the purified polymer also shows the presence of PMA and PStsegments. All these results indicate that well-defined block copolymershave been synthesized.

TABLE 12 Synthesis of Di- and Tri- Block Copolymers Through SequentialAddition^(a) M_(n), SEC M_(w)/M_(n) Monomer (First (First M_(n), calc.M_(n), SEC M_(n), NMR M_(w)/M_(n) Sequence block) block) (Co-polymer)(Co-Polymer) (Co-polymer) (Co-polymer) PMA-PSt 6040 1.25 8920 8300 —1.20 ″ 5580 1.20 10900 10580 — 1.12 ″ 15100 1.14 20700 21700 — 1.2 ″10000 1.25 21800 29000 27500 1.2 ″ 3900 1.25 18700 21400 — 1.13PSt-PMA-PSt 9000 1.25 23800 26100 25500 1.40 ″ 12400 1.25 23800 24200 —1.15 ″ 4000 1.25 12100 19200 18500 1.13 PMA-PSt-PMA 5300 1.13 1290012600 — 1.25 ″ 7700 1.14 21700 21300 — 1.20 ^(a)All polymerizations werecarried out at 110° C. ^(b)Initiators used: di-block copolymer:1-phenylethyl bromide; tri-block copolymers: α,α′-dibromoxylene

ATRP is superior to living ionic polymerization for producingwell-controlled block copolymers. First of all, the experimentalconditions are relatively mild. Furthermore, cross-propagation isfacile, leading to block copolymerization regardless of monomer additionorder, as exemplified by the MA and St copolymerization above. Moreover,tri-block copolymers can be easily obtained by using a di-functionalinitiator. As expected, star-shaped block copolymers can be obtained byusing multi-functional alkyl halides.

Example 31 Star-Shaped Polymer

(i) Synthesis of 4- and 6-Arm Star Shaped PSt using1,2,4,5-tetrakis(bromomethyl)benzene and Hexakis(bromomethyl)Benzene asInitiator.

Table 13 lists the results regarding synthesis of four-arm and six-armstar-shaped PSt using 1,2,4,5-tetrakis(bromomethyl)benzene andhexakis(bromomethyl)benzene as initiator, respectively. The molecularweight distribution is fairly narrow, i.e., M_(w)/M_(n)<1.3 The M_(n) ofthese star-shaped polymers linearly increases with monomer conversion,indicating the presence of negligible amount of chain in transferreactions (data not shown).

A key question involves whether the forming polymers have six or fourarms. Thus, ATRP of deuterated styrene was performed usinghexakis(bromomethyl)benzene as an initiator in the presence of 2 molarequiv. of CuBr and 6 molar equiv of bipy at 110° C., the sameexperimental conditions employed for synthesizing the six-arm PSt listedin Table 13. Except for the observation of a —CH₂— resonance at ca. 1.55ppm, the ¹H NMR signals corresponding to —CH₂Br, which usually resonateat ca. 5.0 ppm, cannot be” detected at all in the ¹H NMR spectrum of thePSt-d₈. This provides strong evidence that a six-arm PSt-d₈ wasproduced.

TABLE 13 Synthesis of 4- and 6-Arm PSt Using C₆H₂(CH₂—Br)₄ andC₆(CH₂—Br)₆ as Initiators at 110° C. Yield, M_(n), M_(n), Time, h %calc. SEC M_(n)/M_(n)  4.75^(b) 90 9000 12300 1.65  5^(b) 90 27000 311001.29 71^(b) 85 51200 62400 1.23 16^(c) 92 13000 11800 1.30 16^(c) 8936400 28700 1.25 a: [R—Br]₀/[CuBr]₀/[bpy]₀ = 1/2/6; ^(b)six-arm;^(c)four-arm

(ii) Synthesis of 4- and 6-Arm Star-Shaped PMA and PMMA using 1,2,4,5tetrakis(bromomethyl)benzene and Hexakis(Bromomethyl)Benzene asInitiator

As noted in Table 14, 4- and 6-arm PMA and PMMA can also be synthesizedby using the same technique for star-shaped St polymerization. However,it may be advantageous to lower the concentration of the catalyst (e.g.,CuBr—bipy), otherwise gelation may occur at a relatively low monomerconversion.

This appears to confirm the radical process of ATRP. On the other hand,it also suggests that the compact structure of growing polymer chainsmay affect the “living” course of ATRP, since at the same concentrationof initiating system, MA and MMA ATRP represents a rather controlledprocess, when a mono-functional initiator was used.

TABLE 14 Synthesis of 4- and 6-Arm PMA and PMMA Using C₆H₂(CH₂—Br)₄ andC₆(CH₂—Br)₆ as Initiator at 110° C. R—Br/ Time, Yield, M_(n), M_(n),CuBr/bpy polymer h % calc SEC M_(n)/M_(w) 1/2/6 C₆(PMA)₆ 5 95 9500 105001.55 ″ ″ 4 90 9000 9700 1.65 ″ C₆(PMMA)₆ 4.5 92 9100 12000 1.75 ″C₆H₂(PMA)₄ 25 gel 20000 — — ″ C₆H₂(PMA)₄ 25 gel 40000 — — 1/1/3 ″ 18 959500 6750 1.23 ″ C₆H₂(PMMA)₄ 20 0.90 9000 9240 1.72 ″ ″ 20 0.91 1820017500 1.49 a: Polymerization at 110° C.

Example 32 Graft Technique

Well-defined comb-shaped PSt has been successfully obtained using PCMSas an ATRP initiator. Table 15 shows the SEC results of final polymers.The MWD is rather narrow.

TABLE 15 Synthesis of Graft Copolymers Using PCMS (DP_(n) = 11) asInitiator^(a) Time, Yield, M_(n), Monomer hr % SEC M_(w)/M_(n) St^(b) 1895 18500 1.40 St^(b) 18 90 38500 1.35 St^(b) 18 85 80500 1.54 BA 15 9518400 1.60 MMA 15 95 37700 1.74 BA^(c) 22 90 24000 1.46 MMA^(c) 22 9046500 1.47 MMA^(c) 22 85 51100 1.44 ^(a)Polymerization at 130° C. inbulk. ^(b)Taken from Example 27. ^(c)Polymerization in 50% ethyl acetatesolution.

Similar to 4- and 6-arm polymers, a key question is whether all chlorineatoms in PCMS participate in the ATRP. A comparison of the ¹H NMRspectra of PCMS and PSt-d₈-g-PCMS shows that the resonances at ca. 5ppm, corresponding to CH₂Cl in PCMS, completely disappear, suggestingthe formation of pure PSt comb-copolymer.

Example 33 Synthesis of ABA Block Copolymers with B=2-EthylhexylAcrylate

(a) Synthesis of Center B Block (α,ω-Dibromopoly(2-Ethylhexyl Acrylate))

To a 50 ml round bottom flask, CuBr (0.032 g), dTBiby (0.129 g) andα,α′-dibromo-p-xylene (0.058 g) were added. The flask was then sealedwith a rubber septum. The flask was degassed by applying a vacuum andbackfilling with argon. Degassed and deinhibited racemic 2-ethylhexylacrylate (10.0 ml) was then added via syringe. Degassed diphenyl ether(10.0 ml) was also added by syringe. The reaction was heated to 100° C.and stirred for 24 hours. Conversion by ¹H NMR was >90%. M_(n)=40,500;M_(w)/M_(n)=1.35.

(b) A=Methyl Methacrylate

To the reaction mixture obtained in Example 33(a) containing thepoly(2-ethylhexyl acrylate), methyl methacrylate (4.53 ml) was added bysyringe. the reaction was stirred at 100° C. for 8 hours. Conversion ofMMA >90%. Mn (overall)=58,000; M_(w)/M_(n)=1.45.

(c) A=Acrylonitrile

The experiment of Example 33(a) was repeated. To the reaction mixturecontaining the (2-ethylhexyl acrylate) (M_(n)=40,500; M_(w)/M_(n)=1.35),acrylonitrile (5.44 ml) was added by syringe. The reaction was stirredat 100° C. for 72 hours. Conversion of acrylonitrile=35%. M_(n)(overall)=47,200; M_(w)/M_(n)=1.45.

Example 34 Synthesis of MMA-BA-MMA Block Copolymer Synthesis ofα,ω-Dibromopoly(butyl acrylate):

To a 50 ml round bottom flask, α,α′-dibromo-p-xylene (0.0692 g), CuBr(0.0376 g), and 2,2′-bipyridyl (0.1229 g) were added and sealed with arubber septum. The flask was then evacuated and filled with argon threetimes. Previously degassed butyl acrylate (15.0 ml) and benzene (15.0ml) were added via syringe. The reaction was heated to 100° C. for 48hours, after which time the conversion was 86.5%, as determined by ¹HNMR. The reaction mixture was poured into cold methanol (−78° C.) toprecipitate the polymer. The precipitate was filtered. The obtainedsolid was a tacky, highly viscous oil. M_(n)=49,000, M_(w)/M_(n)=1.39.

Synthesis of Poly(MMA-BA-MMA):

In a round bottom flask, α,ω-dibromopoly(butyl acrylate) (2.0 g), CuBr(0.0059:g), 2,2′-bipyridyl (0.0192 g) and dimethoxybenzene (2.0 g) wereadded. THe flask was sealed with a rubber septum and placed under anargon atmosphere as described above for the synthesis ofα,ω-dibromopoly(butyl acrylate). Degassed methyl methacrylate (0.73 ml)was added via syringe. The reaction was heated to 100° C. for 5.25hours. The conversion was determined to be 88.8% by ¹H NMR. The reactionmixture was poured into methanol to precipitate the polymer. The solidwhich was obtained was colorless and rubbery. M_(n)=75,400,M_(w)/M_(n)=1.34.

Example 35 Synthesis of Poly(p-t-Butylstyrene)

To a 100 ml round bottom flask, dimethoxybenzene (25.0 g), CuCl (0.2417g) and 2,2′-bipyridyl (1.170 g) were added and sealed with a rubberseptum. The flask was then evacuated and filled with argon three times.Degassed t-butylstyrene (28.6 ml) and 1-phenylethyl chloride (0.33 ml)were added via syringe. The reaction was then heated to 130° C. for 8.5hours. The reaction mixture was precipitated into methanol, filtered anddried. M_(n)=5531. M_(w)/M_(n)=1.22.

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that within the scope of the appended claims, theinvention may be practiced otherwise than as specifically describedherein.

We claim:
 1. A (co)polymer having a molecular weight distribution ofless than 2 and having a general formula selected from the groupconsisting of: A—{(M¹)_(i)(M²)_(j)}—X, A—{(M¹)_(i)(M²)_(j)(M³)_(k)}—X,A—{(M¹)_(i)(M²)_(j)(M³)_(k) . . . (M^(u))_(α)}—X, A—(M¹)_(p)—(M²)_(p)—X,A—(M¹)_(p)—(M²)_(p)—(M³)_(p)—X, A—(M¹)_(p)—(M²)_(p)—(M³)_(p)— . . .—(M^(u))_(p)—X, X—M_(p)—(A′)—M_(p)—X,X—{(M¹)_(i)(M²)_(j)}—(A′)—{(M¹)_(i)(M²)_(j)}—X,X—{(M¹)_(i)(M²)_(j)(M³)_(k)}—(A′)—{(M¹)_(i)(M²)_(j)(M³)_(k)}—X,X—{(M¹)_(i)(M²)_(j)(M³)_(k) . . .(M^(u))_(α)}—(A′)—{(M¹)_(i)M²)_(j)(M³)_(k) . . . (M^(u))_(α)}—X,X—(M²)_(p)—(M¹)_(p)—(A′)—(M¹)_(p)—(M²)_(p)—X,X—(M³)_(p)—(M²)_(p)—(M¹)_(p)—(A′)—(M¹)_(p)—(M²)_(p)—(M³)_(p)—X,X—{(M^(u))_(p)— . . .—(M³)_(p)—(M²)_(p)—(M¹)_(p)—(A′)—(M¹)_(p)—(M²)_(p)—(M³)_(p)— . . .—(M^(u))_(p)}—X, A′—({(M¹)_(i)(M²)_(j)}—X)_(z),A′—({(M¹)_(i)(M²)_(j)(M³)_(k)}—X)_(z), A′—({(M¹)_(i)(M²)_(j)(M³)_(k) . .. (M^(u))_(α)}—X)_(z), A′—{(M¹)_(p)—X}_(z),A′—{(M¹)_(p)—(M²)_(p)—X}_(z), A′—{(M¹)_(p)—(M²)_(p)—(M³)_(p)—X}_(z), andA′—{(M¹)_(p)—(M²)_(p)—(M³)_(p)— . . . —(M^(u))_(p)—X}_(z) wherein X is aradically transferable atom, a radically transferable group, a halogen,Cl, Br, I, OR¹⁰, SR¹⁴, SeR¹⁴, OC(═O)R¹⁴, OP(═O)R¹⁴, OP(═O)(OR¹⁴)₂,O—N(R¹⁴)₂, S—C(═S)N(R¹⁴)₂, CN, NC, SCN, CNS, OCN, CNO, N₃, OH, (O)_(½),C₁-C₆-alkoxy, (SO₄), PO₄, HPO₄, H₂PO₄, triflate, hexafluorophosphate,methanesulfonate, arylsulfonate, carboxylic acid halide, R¹⁵CO₂, H, NH₂,COOH, or CONH₂, where R¹⁴ is aryl or a straight or branched C₁-C₂₀ alkylgroup or where an N(R¹⁴)₂ group is present, the two R¹⁴ groups may bejoined to form a 5-, 6- or 7-member heterocyclic ring, R¹⁵ is H or astraight or branched C₁-C₆ alkyl group, aryl or aryl substituted 1 to 5times with a halogen, and R¹⁰ is an alkyl of from 1 to 20 carbon atomsor an alkyl of from 1 to 20 carbon atoms in which each of the hydrogenatoms may be replaced by a halide, alkenyl of from 2 to 20 carbon atoms,alkynyl of from 2 to 10 carbon atoms, phenyl, phenyl substituted withfrom 1 to 5 halogen atoms or alkyl groups with from 1 to 4 carbon atoms,aralkyl, aryl, aryl substituted alkyl, in which the aryl group is phenylor substituted phenyl and the alkyl group is from 1 to 6 carbon atoms; Ais a residue of an initiator, A′ is a residue of an multifunctionalinitiator and z is 3 or more, wherein the initiator is of the formula:R¹¹C(═O)—X; R¹¹R¹²R¹³Si—X; R¹¹R¹²N—X; R¹¹N—X₂;(R¹¹)_(n)P(O)_(m)—X_(3−n); or (R¹¹)(R¹²O)P(O)_(m)—X  where: R¹¹, R¹² andR¹³ are each independently selected from the group consisting of H,halogen, C₁-C₂₀ alkyl, C₃-C₈ cycloalkyl, R⁸ ₃Si, C(═Y)R⁵, C(═Y)NR⁶R⁷,COCl, OH, CN, C₂-C₂₀ alkenyl or alkynyl, oxiranyl, glycidyl, C₂-C₆alkylene or alkenylene substituted with oxiranyl or glycidyl, aryl,heterocyclyl, aralkyl, aralkenyl, aryl-substituted alkenyl, and alkenylis vinyl which may be substituted with one or two C₁-C₆ alkyl groupsand/or halogen atoms, C₁-C₆ alkyl in which from 1 to all of the hydrogenatoms are replaced with halogen and C₁-C₆ alkyl substituted with from 1to 3 substituents selected from the group consisting of C₁-C₄ alkoxy,aryl, heterocyclyl, C(═Y)R⁵, C(═Y)NR⁶R⁷, oxiranyl and glycidyl, with theprovisio that no more than 2 of R¹¹, R¹² and R¹³ are H; R⁵ is C₁₋₂₀alkyl group, C₁₋₂₀ alkylthio group, OR²⁴ wherein R²⁴ is H or an alkalimetal, C₁-C₂₀ alkoxy group, aryl, aralkyl, heterocyclyl, aryloxy orheterocyclyloxy, R⁶ and R⁷ are each independently H or C₁₋₂₀ alkylgroup, or R⁶ and R⁷ may be joined together to form a C₂₋₇ alkylenegroup, thus forming a 3- to 8-membered ring, and R⁸ is H, straight orbranched C₁-C₂₀ alkyl or aryl; m is 0 or 1; and n is 0, 1 or 2; M¹, M²,M³, . . . up to M^(u) independently each represent a monomer unitderived from a radically (co)polymerizable monomer, wherein any adjacentblocks are not identical but wherein non-adjacent blocks may beidentical; each i, j, k . . . and a independently represents an averagemolar ratio of monomer units in each block to the total number of molesof monomer units in the copolymer or an individual branch of thecopolymer; and p is an average degree of polymerization for each blockand is independently selected for each block wherein the (co)polymer orthe block thereof has an average degree of polymerization of at least 3or wherein the weight average molecular weight or the number averagemolecular weight of the (co)polymer or a block thereof is at least 250g/mol.
 2. A (co)polymer selected from the group consisting ofwater-soluble, water-miscible, water-swellable, and water-dispersible(co)polymers, comprising a molecular weight distribution in one or moresegments of less than 2, the (co)polymer having a general formulaselected from the group consisting of: A—{(M¹)_(p)}—X,A—{(M¹)_(i)(M²)_(j)}—X, A—{(M¹)_(i)(M²)_(j)(M³)_(k)}—X,A—{(M¹)_(i)(M²)_(j)(M³)_(k) . . . (M^(u))_(α)}—X, A—(M¹)_(p)—(M²)_(p—X,)A—(M¹)_(p)—(M²)_(p)—(M³)_(p)—X, A—(M¹)_(p)—(M²)_(p)—(M³)_(p)— . . .—(M^(u))_(p)—X, X—M¹ _(p)—(A′)—M¹p—X,X—{(M¹)_(i)(M²)_(j)}—(A′)—{(M¹)_(i)(M²)_(j)}—X,X—{(M¹)_(i)(M²)_(j)(M³)_(k)}—(A′)—{(M¹)_(i)(M²)_(j)(M³)_(k)}—X,X—{(M¹)_(i)(M²)_(j)(M³)_(k) . . .(M^(u))_(α)}—(A′){(M¹)_(i)(M²)_(j)(M¹)_(k) . . . (M^(u))_(α)}—X,X—(M²)_(p)—(M¹)_(p)—(A′)—(M¹)_(p)—(M²)_(p)—X,X—(M³)_(p)—(M²)_(p)—(M¹)_(p)—(A′)—(M¹)_(p)—(M²)_(p)—(M³)_(p)—X,X—(M^(u))_(p)— . . .—(M³)_(p)—(M²)_(p)—(M¹)_(p)—(A′)—(M¹)_(p)—(M²)_(p)—(M³)_(p)— . . .—(M^(u))_(p)—X, A′—{(M¹)_(p)—X}_(z), A′—({(M¹)_(i)(M²)_(j)}—X)_(z),A′—({(M¹)_(i)(M²)_(j)(M³)_(k)}—X)_(z), A′—({(M¹)_(i)(M²)_(j)(M³)_(k) . .. (M^(u))_(α)}—X)_(z), A′—{(M¹)_(p)—(M²)_(p)—X}_(z),A′—{(M¹)_(p)—(M²)_(p)—(M³)_(p)—X}_(z), andA′—{(M¹)_(p)—(M²)_(p)—(M³)_(p)— . . . —(M^(u))_(p)—X}_(z) wherein X is aradically transferable atom or a radically transferable group, ahalogen, Cl, Br, I, OR¹⁰, SR¹⁴, SeR¹⁴, OC(═O)R¹⁴, OP(═O)R¹⁴,OP(═O)(OR¹⁴)₂, O—(R¹⁴)₂, S—C(═S)N(R¹⁴)₂, CN, NC, SCN, CNS, OCN, CNO, N₃,OH, O, C₁-C₆-alkoxy, (SO₄), PO₄, HPO₄, H₂PO₄, triflate,hexafluorophosphate, methanesulfonate, arylsulfonate, carboxylic acidhalide, R¹⁵CO₂, H, NH₂, COOH, or CONH₂, where R¹⁴ is aryl or a straightor branched C₁-C₂₀ alkyl group or where an N(R¹⁴)₂ group is present, thetwo R¹⁴ groups may be joined to form a 5-, 6- or 7-member heterocyclicring, R¹⁵ is H or a straight or branched C₁-C₆ alkyl group, aryl or arylsubstituted 1 to 5 times with a halogen, and R¹⁰ is an alkyl of from 1to 20 carbon atoms or an alkyl of from 1 to 20 carbon atoms in whicheach of the hydrogen atoms may be replaced by a halide, alkenyl of from2 to 20 carbon atoms, alkynyl of from 2 to 10 carbon atoms, phenyl,phenyl substituted with from 1 to 5 halogen atoms or alkyl groups withfrom 1 to 4 carbon atoms, aralkyl, aryl, aryl substituted alkyl, inwhich the aryl group is phenyl or substituted phenyl and the alkyl groupis from 1 to 6 carbon atoms; A is a residue of an initiator; A′ is aresidue of an multifunctional initiator, wherein z is 3 or more, whereinthe initiator is of the formula: R¹¹C(═O)—X; R¹¹R¹²R¹³Si—X; R¹¹R¹²N—X;R¹¹N—X₂; (R¹¹)_(n)P(O)_(m)—X_(3−n); or (R¹¹)(R¹²O)P(O)_(m)—X  where:R¹¹, R¹² and R¹³ are each independently selected from the groupconsisting of H, halogen, C₁-C₂₀ alkyl, C₃-C₈ cycloalkyl, R⁸ ₃Si,C(═Y)R⁵, C(═Y)NR⁶R⁷, COCl, OH, CN, C₂-C₂₀ alkenyl or alkynyl, oxiranyl,glycidyl, C₂-C₆ alkylene or alkenylene substituted with oxiranyl orglycidyl, aryl, heterocyclyl, aralkyl, aralkenyl, aryl-substitutedalkenyl, and alkenyl is vinyl which may be substituted with one or twoC₁-C₆ alkyl groups and/or halogen atoms, C₁-C₆ alkyl in which from 1 toall of the hydrogen atoms are replaced with halogen and C₁-C₆ alkylsubstituted with from 1 to 3 substituents selected from the groupconsisting of C₁-C₄ alkoxy, aryl, heterocyclyl, C(═Y)R⁵, C(═Y)NR⁶R⁷,oxiranyl and glycidyl, with the provisio that no more than 2 of R¹¹, R¹²and R¹³ are H; R⁵ is C₁₋₂₀ alkyl group, C₁₋₂₀ alkylthio group, OR²⁴,wherein R²⁴ is H or an alkali metal, C₁-C₂₀ alkoxy group, aryl, aralkyl,heterocyclyl, aryloxy or heterocyclyloxy, R⁶ and R⁷ are eachindependently H or C₁₋₂₀ alkyl group, or R⁶ and R⁷ may be joinedtogether to form a C₂₋₇ alkylene group, thus forming a 3- to 8-memberedring, and R⁸ is H, straight or branched C₁-C₂₀ alkyl or aryl; with theproviso that when R¹¹ is directly bonded to S or O, R⁸ may be an alkalimetal or an ammonium group; m is 0 or 1; and n is 0, 1 or 2; M¹, M², M³,. . . up to M^(u)independently each represent amonomer unit derived froma radically (co)polymerizable monomer wherein any adjacent blocks arenot identical but wherein non-adjacent blocks may be identical, andwherein at least one of the radically (co)polymerizable monomers has theformula:

 wherein R¹and R² are independently selected from the group consistingof H, halogen, CN, aryl, straight or branched C₁₋₁₀ alkyl group whichmay be substituted, unsaturated straight or branched alkenyl or alkynylhaving 2 to 10 carbon atoms which may be substituted, C₃-C₈ cycloalkylwhich may be substituted, heterocyclyl wherein each H atom may bereplaced with halogen atoms or C₁-C₆ alkyl or alkoxy groups and in whichone or more optionally present nitrogen atoms may be quaternized with Hor C₁-C₄ alkyl, NR⁸ ₂, N⁺R⁸ ₃, COOR⁹, wherein R⁹ is H, an alkali metal,or a C₁-C₂₀ alkyl group, C(═Y)R⁵, C(═Y)NR⁶R⁷, YC(═Y)R⁸, YS(═Y)₂R⁸,YS(═Y)₂YR⁸, P(YR⁸)₂,P(═Y)(YR⁸)₂ and P(═Y)R⁵ ₂, wherein Y may be NR⁹, Sor O wherein R³ and R⁴ are independently selected from the groupconsisting of H, halogen, CN, C₁-C₆ alkyl and COOR⁹; or R¹ and R³ may bejoined to form a group of the formula (CH₂)_(n′) which may besubstituted or a group of the formula C(═O)—Y—C(═O), where n′ is from 2to 6 and Y is as defined above; and wherein at least two of R¹, R², R³,and R⁴ are H or halogen and wherein at least one of R¹, R², R³, and R⁴is or is substituted with heterocyclyl having one or more nitrogen atomsquaternized with H or C₁-C₄ alkyl, NR⁸ ₂, N⁺R⁸ ₃, COOR⁹, C(═Y)R⁵,C(═Y)NR⁶R⁷, YC(═Y)R⁸, YS(═Y)R⁸,YS(═Y)₂R⁸, YS(═Y)₂YR⁸, P(YR⁸)₂ or P(═Y)R⁸₂, or hydroxy-substituted C₁-C₁₀ alkyl; each i, j, k . . . and aindividually represents an average molar ratio of monomer units in theblocks M¹, M², M³, . . . up to M^(u) to the total number of moles ofmonomer units in the copolymer or an individual branch of the copolymer;and p is an average degree of polymerization for each block and isindependently selected for each block such that either the averagedegree of polymerization of each (co)polymer or a block thereof is atleast 3 or the number average molecular weight of each (co)polymer orblock thereof is at least 250 g/mol.
 3. A gradient copolymer of theformula: A—M¹ _(p)—(M¹ _(a)M² _(b))₁— . . . —(M¹ _(a)M² _(b))_(y)—M²_(p)—X, wherein X is a radically transferable atom or a radicallytransferable group, a halogen, Cl, Br, I, OR¹⁰, SR¹⁴, SeR¹⁴, OC(═O)R¹⁴,OP(═O)R¹⁴, OP(═O)(OR¹⁴)₂, O—N(R¹⁴)₂, S—C(═S)N(R¹⁴)₂, CN, NC, SCN, CNS,OCN, CNO, N₃, OH, O, C₁-C₆-alkoxy, (SO₄), PO₄, HPO₄, H₂PO₄, triflate,hexafluorophosphate, methanesulfonate, arylsulfonate, carboxylic acidhalide, R¹⁵CO₂, H, NH₂, COOH, or CONH₂, where R¹⁴ is aryl or a straightor branched C₁-C₂₀ alkyl group or where an N(R¹⁴)₂ group is present, thetwo R¹⁴ groups may be joined to form a 5-, 6- or 7-member heterocyclicring, R¹⁵ is H or a straight or branched C₁-C₆ alkyl group, aryl or arylsubstituted 1 to 5 times with a halogen, and R¹⁰ is an alkyl of from 1to 20 carbon atoms or an alkyl of from 1 to 20 carbon atoms in whicheach of the hydrogen atoms may be replaced by a halide, alkenyl of from2 to 20 carbon atoms, alkynyl of from 2 to 10 carbon atoms, phenyl,phenyl substituted with from 1 to 5 halogen atoms or alkyl groups withfrom 1 to 4 carbon atoms, aralkyl, aryl, aryl substituted alkyl, inwhich the aryl group is phenyl or substituted phenyl and the alkyl groupis from 1 to 6 carbon atoms; A is a residues of an initiator; whereinthe initiator is of the formula: R¹¹C(═O)—X; R¹¹R¹²R¹³Si—X; R¹¹R¹²N—X;R¹¹N—X₂; (R¹¹)_(n)P(O)_(m)—X_(3−n); or (R¹¹)(R¹²O)P(O)_(m)—X  where:R¹¹, R¹² and R¹³ are each independently selected from the groupconsisting of H, halogen, C₁-C₂₀ alkyl, C₃-C₈ cycloalkyl, R⁸ ₃Si,C(═Y)R⁵, C(═Y)NR⁶R⁷, COCl, OH, CN, C₂-C₂₀ alkenyl or alkynyl, oxiranyl,glycidyl, C₂-C₆ alkylene or alkenylene substituted with oxiranyl orglycidyl, aryl, heterocyclyl, aralkyl, aralkenyl, aryl-substitutedalkenyl, and alkenyl is vinyl which may be substituted with one or twoC₁-C₆ alkyl groups and/or halogen atoms, C₁-C₆ alkyl in which from 1 toall of the hydrogen atoms are replaced with halogen and C₁-C₆ alkylsubstituted with from 1 to 3 substituents selected from the groupconsisting of C₁-C₄ alkoxy, aryl, heterocyclyl, C(═Y)R⁵, C(═Y)NR⁶R⁷,oxiranyl and glycidyl, with the provisio that no more than 2 of R¹¹, R¹²and R¹³ are H; R⁵ is C₁₋₂₀ alkyl group, C₁₋₂₀ alkylthio group, OR²⁴wherein R²⁴ is H or an alkali metal, C₁₋₂₀alkoxy group, aryl, aralkyl,heterocyclyl, aryloxy or heterocyclyloxy, R⁶ and R⁷ are eachindependently H or C₁₋₂₀ alkyl group, or R⁶ and R⁷ may be joinedtogether to form a C₂₋₇ alkylene group, thus forming a 3- to 8-memberedring, and R⁸ is H, straight or branched C₁-C₂₀ alkyl or aryl; with theproviso that when R⁸ is directly bonded to S or O, R⁸ may be an alkalimetal or an ammonium group; m is 0 or 1; and n is 0, 1 or 2; M¹ and M²each represent monomer units derived from radically (co)polymerizablemonomers; y is the total number of blocks; a is an average molarpercentage of M¹ in each block determined independently for each blockof the copolymer indicated by the parenthesis; b is a molar percentageof M² in each block determined independently for each block of thecopolymer indicated by the parenthesis; such that a+b=100 percent foreach block, and the molar percentage of M¹changes for each subsequentblock along the length of each polymer chain from the residue of theinitiator to the radically transferable atom or group or a group derivedtherefrom, block y; and p is an average degree of polymerization of atleast 2 selected independently for each monomer unit.
 4. The gradientcopolymer of claim 3, wherein the radically (co)polymerizable monomershave different reactivities.
 5. An amphiphilic (co)polymer having aformula selected from the group consisting of: A—{(M¹)_(i)(M²)_(j)}—X,A—{(M¹)_(i)(M²)_(j)(M³)_(k)}—X, A—{(M¹)_(i)(M²)_(j)(M³)_(k) . . .(M^(u))_(α)}—X, A—(M¹)_(p)—(M²)_(p)—X, A—(M¹)_(p)—(M²)_(p)—(M³)_(p)—X,A—(M¹)_(p)—(M²)_(p)—(M³)_(p)— . . . —(M^(u))_(p)—X,A′—({(M¹)_(i)(M²)_(j)}—X)_(z), A′—({(M¹)_(i)(M²)_(j)(M³)_(k)}—X)_(z),A′—({(M¹)_(i)(M²)_(j))(M³)_(k) . . . (M^(u))_(α)}—X)_(z),A′—{(M¹)_(p)—(M²)_(p)—X}_(z), A′—{(M¹)_(p)—(M²)_(p)—(M³)_(p)—X}_(z), andA′—{(M¹)_(p)—(M²)_(p)—(M³)_(p)— . . . —(M^(u))_(p))—X}_(z) wherein X isa radically transferable atom or a radically transferable group, ahalogen, Cl, Br, I, OR¹⁰, SR¹⁴, SeR¹⁴, OC(═O)R¹⁴, OP(═O)R¹⁴,OP(═O)(OR¹⁴)₂, O—(R¹⁴)₂, S—C(═S)N(R¹⁴)₂, CN, NC, SCN, CNS, OCN, CNO, N₃,OH, O, C₁-C₆-alkoxy, (SO₄), PO₄, HPO₄, H₂PO₄, triflate,hexafluorophosphate, methanesulfonate, arylsulfonate, carboxylic acidhalide, R¹⁵CO₂, H, NH₂, COOH, or CONH₂, where R¹⁴ is aryl or a straightor branched C₁-C₂₀ alkyl group or where an N(R¹⁴)₂ group is present, thetwo R¹⁴ groups may be joined to form a 5-, 6- or 7- member heterocyclicring, R¹⁵ is H or a straight or branched C₁-C₆ alkyl group, aryl or arylsubstituted 1 to 5 times with a halogen, and R¹⁰ is an alkyl of from 1to 20 carbon atoms or an alkyl of from 1 to 20 carbon atoms in whicheach of the hydrogen atoms may be replaced by a halide, alkenyl of from2 to 20 carbon atoms, alkynyl of from 2 to 10 carbon atoms, phenyl,phenyl substituted with from 1 to 5 halogen atoms or alkyl groups withfrom 1 to 4 carbon atoms, aralkyl, aryl, aryl substituted alkyl, inwhich the aryl group is phenyl or substituted phenyl and the alkyl groupis from 1 to 6 carbon atoms; A is a residue of an initiator; A′ is aresidue of an multifunctional initiator; wherein z is 2 or more, whereinthe initiator is of the formula: R¹¹C(═O)—X; R¹¹R¹²R¹³Si—X; R¹¹R¹²N—X;R¹¹N—X₂; (R¹¹)_(n)P(O)_(m)—X_(3−n); or (R¹¹)(R¹²O)P(O)_(m)—X  where:R¹¹, R¹² and R¹³ are each independently selected from the groupconsisting of H, halogen, C₁-C₂₀ alkyl, C₃-C₈ cycloalkyl, R⁸ ₃Si,C(═Y)R⁵, C(═Y)NR⁶R⁷, COCl, OH, CN, C₂-C₂₀ alkenyl or alkynyl, oxiranyl,glycidyl, C₂-C₆ alkylene or alkenylene substituted with oxiranyl orglycidyl, aryl, heterocyclyl, aralkyl, aralkenyl, aryl-substitutedalkenyl, and alkenyl is vinyl which may be substituted with one or twoC₁-C₆ alkyl groups and/or halogen atoms, C₁-C₆ alkyl in which from 1 toall of the hydrogen atoms are replaced with halogen and C₁-C₆ alkylsubstituted with from 1 to 3 substituents selected from the groupconsisting of C₁-C₄ alkoxy, aryl, heterocyclyl, C(═Y)R⁵, C(═Y)NR⁶R⁷,oxiranyl and glycidyl, with the provisio that no more than 2 of R¹¹, R¹²and R¹³ are H; m is 0 or 1; and n is 0, 1 or 2; M¹, M², M³, . . . up toM^(u) independently each represent a monomer unit derived a radically(co)polymerizable monomer, wherein any adjacent blocks are not identicalbut wherein non-adjacent blocks may be identical, and wherein at leastone of the radically (co)polymerizable monomers has the formula:

 wherein R¹ and R² are independently selected from the group consistingof H, halogen, CN, aryl, straight or branched alkyl of from 1 to 10carbon atoms which may be substituted, unsaturated straight or branchedC₂₋₁₀ alkenyl or alkynyl which may be substituted, C₃-C₈ cycloalkylwhich may be substituted, heterocyclyl in which each H atom may beindependently replaced with halogen atoms or C₁-C₆ alkyl or alkoxygroups and in which one or more nitrogen atoms when present may bequaternized with H or C₁-C₄ alkyl, NR⁸ ₂, N⁺R⁸ ₃, COOR⁹, wherein R⁹ isH, an alkali metal, or a C₁-C₂₀ alkyl group, C(═Y)R⁵, C(═Y)NR⁶R⁷,YC(═Y)R⁸, YS(═Y)R⁸, YS(═Y)₂YR⁸, P(YR⁸)₂, P(═Y)(YR⁸)₂ and P(═Y)R⁵ ₂,where Y may be NR⁹, S or O, wherein R⁵ is C₁₋₂₀ alkyl, C₁₋₂₀ alkylthio,OR²⁴ where R²⁴ is H or an alkali metal, C₁₋₂₀ alkoxy, aryl, aralkyl,heterocyclyl, aryloxy or heterocyclyloxy, group, and R⁶ and R⁷ areindependently H or C₁₋₂₀ alkyl, or R⁶ and R⁷ may be joined together toform a C₂₋₇ alkylene group, thus forming a 3- to 8-membered ring, and R⁸is H, straight or branched C₁-C₂₀ alkyl or aryl; with the proviso thatwherein when R⁸ is directly bonded to S or O, R⁸ may be an alkali metalor an ammonium group; and R³ and R⁴ are independently selected from thegroup consisting of H, halogen, CN, C₁-C₆ alkyl and COOR⁹; or R¹ and R³may be joined to form a group of the formula (CH₂)_(n)′ which may besubstituted or C(═O)—Y—C(═O), where n′ is from 2 to 6 and Y is asdefined above; and wherein at least two of R¹, R², R³, and R⁴ are H orhalogen and wherein at least one of R¹, R², R³, and R⁴ is or issubstituted with heterocyclyl in which one or more nitrogen atoms isquaternized with H or C₁-C₄ alkyl, NR⁸ ₂, N⁺R⁸ ₃, COOR⁹, C(═Y)R⁵,C(═Y)NR⁶R⁷, YC(═Y)R⁸, YS(═Y)R⁸, YS(═Y)₂R⁸, YS(═Y)₂YR⁸, P(YR⁸)₂,P(═Y)(YR⁸)₂ or P(═Y)R⁸ ₂, or hydroxy-substitued C₁-C₁₀ alkyl; each i, j,k . . . and a independently represents an average molar ratio of themoles of monomer units M¹, M², M³, . . . up to M^(u)to the total numberof moles of monomer units in the copolymer or an individual branch ofthe copolymer; and p is an average degree of polymerizationindependently selected for each block wherein either the average degreeof polymerization for each block is at least 3 or a number averagemolecular weight of each block is at least 250 g/mol.
 6. A periodiccopolymer of the formula: A—{(M¹)_(p)(M²)_(p)(M³)_(p) . . .(M^(u))_(p)}—X, or A′—{(M¹)_(p)(M²)_(p)(M³)_(p) . . .(M^(u))_(p)—X}_(z), wherein X is a radically transferable atom or aradically transferable group, a halogen, Cl, Br, I, OR¹⁰, SR¹⁴, SeR¹⁴,OC(═O)R¹⁴, OP(═O)R¹⁴, OP(═O)(OR¹⁴)₂, O—(R¹⁴)₂, S—C(═S)N(R¹⁴)₂, CN, NC,SCN, CNS, OCN, CNO, N₃, OH, O, C₁-C₆-alkoxy, (SO₄), PO₄, HPO₄, H₂PO₄,triflate, hexafluorophosphate, methanesulfonate, arylsulfonate,carboxylic acid halide, R¹⁵CO₂, H, NH₂, COOH, or CONH₂, where R¹⁴ isaryl or a straight or branched C₁-C₂₀ alkyl group or where an N(R¹⁴)₂group is present, the two R¹⁴ groups may be joined to form a 5-, 6- or7- member heterocyclic ring, R¹⁵ is H or a straight or branched C₁-C₆alkyl group, aryl or aryl substituted 1 to 5 times with a halogen, andR¹⁰ is an alkyl of from 1 to 20 carbon atoms or an alkyl of from 1 to 20carbon atoms in which each of the hydrogen atoms may be replaced by ahalide, alkenyl of from 2 to 20 carbon atoms, alkynyl of from 2 to 10carbon atoms, phenyl, phenyl substituted with from 1 to 5 halogen atomsor alkyl groups with from 1 to 4 carbon atoms, aralkyl, aryl, arylsubstituted alkyl, in which the aryl group is phenyl or substitutedphenyl and the alkyl group is from 1 to 6 carbon atoms; A is a residueof an initiator: A′ is a residue of an multifunctional initiator;wherein z is 2 or more; M¹, M², M³, . . . up to M^(u) independently eachrepresent a monomer unit derived from a radically (co)polymerizablemonomer wherein the monomer units are distributed in a regular sequencealong each polymeric chain; and p is an average mole fraction of eachmonomeric unit in each polymer chain for each and is independentlyselected for each monomeric unit such that the (co)polymer or a blockthereof has an average degree polymerization of at least 3 or the weightor the number average molecular weight of the (co)polymer or a blockthereof at least is 250 g/mol.
 7. The periodic copolymer of claim 6,wherein A is R¹¹R¹²R¹³C, R¹¹C(O), R¹¹R¹²R¹³Si, R¹¹R¹²N,(R¹¹)_(n)P(O)_(m), (R¹¹O)_(n)P(O)_(m) or (R¹¹)(R¹²O)P(O)_(m); whereinR¹¹, R¹² and R¹³ are each independently selected from the groupconsisting of H, halogen, C₁-C₂₀ alkyl, C₃-C₈ cycloalkyl, R⁵ ₃Si,C(═Y)R⁵, C(═Y)NR⁶R⁷, COCl, OH, CN, C₂-C₂₀ alkenyl or alkynyl, oxiranyl,glycidyl, C₂-C₆ alkylene or alkenylene substituted with oxiranyl orglycidyl, aryl, heterocyclyl, aralkyl, aralkenyl, C₁-C₆ alkyl in whichfrom 1 to all of the hydrogen atoms are replaced with halogen and C₁-C₆alkyl substituted with from 1 to 3 substituents selected from the groupconsisting of C₁-C₄ alkoxy, aryl, heterocyclyl, C(═Y)R⁵, C(═Y)NR⁶R⁷,oxiranyl and glycidyl; with the proviso that no more than two of R¹¹,R¹² and R¹³ are H, wherein R⁵ is C₁₋₂₀ alkyl, C₁₋₂₀ alkylthio, OR²⁴where R²⁴ is H or an alkali metal, C₁₋₂₀ alkoxy, aryl, aralkyl,heterocyclyl, aryloxy or heterocyclyloxy, R⁶ and R⁷ are independently Hor C₁₋₂₀ alkyl, or R⁶ and R⁷ may be joined together to form a C₂₋₅alkylene group, thus forming a 3- to 6-membered ring, and R⁸ is H,straight or branched C₁-C₂₀ alkyl or aryl; m is 0 or 1; and n is 0, 1 or2.
 8. A poly-telechelic polymer having a molecular weight distributionof less than 2, comprising: monomer units derived from radically(co)polymerizable monomers; a terminal hydroxyl group; and a terminalisocyanate group.
 9. The poly-telechelic polymer of claim 8, wherein theterminal hydroxy group is a residue of an initiator.
 10. Thepoly-telechelic polymer of claim 9, wherein the initiator is aninitiating or polymerizable monomer.
 11. The poly-telechelic polymer ofclaim 8, further comprising: a hydroxyl group attached to at least oneof the monomer units.